Opinion for the court filed by Circuit Judge J. SKELLY WRIGHT.
Concurring opinion filed by Chief Judge BAZELON.
Dissenting opinion, in which Circuit Judges TAMM, ■ ROBB, and WILKEY join, filed by Circuit Judge MacKINNON.
J. SKELLY WRIGHT, Circuit Judge:We are required by this case to review once again the National Labor Relations Board’s “right to control” test for determining whether a union has engaged in secondary activity proscribed by Section 8(b)(4)(B) of the National Labor Relations Act, 29 U.S.C. § 158(b)(4)(B) (1970).1 The Board found that the petitioner union, Enterprise Association, had violated Section 8(b)(4)(B) by directing member steamfitters to refuse to comply with their employer’s instruction to install prefabricated climate control units. Although the Board specifically determined that the refusal “was for the purpose of preserving work [the steamfitters] had traditionally performed,”2 the Board nevertheless held it to be secondary activity because the steamfitters’ employer did not have the legal right to control assignment of the work which the union was attempting to preserve.
We have held in two previous decisions, Local 742, Carpenters v. NLRB, 144 U.S.App.D.C. 20, 444 F.2d 895, cert. denied, 404 U.S. 986, 92 S.Ct. 447, 30 L.Ed.2d 371 (1971), and Local 636, Plumbers & Pipefitters v. NLRB, 139 U.S.App.D.C. 165, 430 F.2d 906 (1970), that the right to control test misconstrues Section 8(b)(4)(B) as interpreted by the Supreme Court in National Woodwork Manufacturers Assn. v. NLRB, 386 U.S. 612, 87 S.Ct. 1250, 18 L.Ed.2d 357 (1967). Despite the fact that at least four of our sister circuits have similarly rejected the Board’s position,3 the Board has nevertheless stead*229fastly persisted in applying its test. The Board’s recent attempt to provide an acceptable rationale for its approach and to explain how the disputed test is consistent with the analysis of National Woodwork, supra, has now been approved by the Fourth Circuit in George Koch Sons, Inc. v. NLRB, 490 F.2d 323 (1973). We have reconsidered the right to control test in light of the Board’s rationalization in Koch 4 but we continue to adhere to our previous holdings that the test impermissibly expands the congressionally intended scope of Section 8(b)(4)(B).
I
Petitioner Enterprise Association, a plumbing and pipefitting union, has for many years negotiated a collective bargaining agreement with Hudik-Ross Company, a firm engaged in the business of heating, ventilating, and air conditioning contracting. The agreement which was effective during the period of the union’s allegedly secondary activity contained a provision, Rule IX, which obligated Hudik-Ross to have its employees “cut and thread internal piping in climate control units” which Hudik-Ross contracted to install.5 This cutting and threading was work traditionally performed by employees in the bargaining unit.
The Austin Company is the general contractor and engineer for construction of the Norwegian Home for the Aged in Brooklyn, New York. In January 1972, as a result of competitive bidding, Hudik-Ross was awarded a subcontract to provide the heating, ventilation, and air conditioning work for the Norwegian Home construction. This subcontract incorporated Austin’s specifications that certain heating and air conditioning units manufactured by Slant/Fin Corporation would be installed in the Norwegian Home. The specifications clearly *230indicated that the internal piping for these units was to be cut, threaded, and installed at the Slant/Fin factory, and the Board accepted the trial examiner’s finding that “Hudik was aware of the specifications prior to making its bid and at the time it executed the subcontract” with Austin.6 It is not disputed that this cutting, threading, and installation was the type of work which, under Rule IX of its collective bargaining agreement with the union, Hudik-Ross was obligated to have performed on the jobsite by its employees. However, there is no indication in the record, and the Board made no finding, that Hudik-Ross ever attempted to extricate itself from the pinch of two inconsistent contractual commitments by initiating bargaining with the union concerning a possible relaxation of Rule IX.
Shortly after the Slant/Fin units arrived at the Norwegian Home jobsite, a business agent for the union informed Hudik-Ross that the steamfitters represented by the union would not install the units because their internal piping had been completed at the factory in violation of Rule IX. The refusal to install the Slant/Fin units having delayed completion of the Norwegian Home, Austin filed a complaint with the Board charging that the union was violating Section 8(b)(4)(B) by encouraging individuals employed by Hudik-Ross to refuse to perform certain services with an object of forcing or requiring Austin and HudikRoss to cease using the products of Slant/Fin. Both the administrative law judge (ALJ) and the Board sustained Austin’s charge, despite the fact that there- was no evidence indicating that the union or its affiliates had ever attempted to organize Slant/Fin or that the union was even aware of the organizational status or working conditions of the Slant/Fin employees.7 Indeed, the Board concluded that the union’s refusal to let Hudik-Ross employees install the units “was for the purpose of preserving work they had traditionally performed.” 8 However, applying its right to control doctrine,9 the Board found *231that the union’s actions constituted impermissible secondary pressure against Hudik-Ross because Hudik-Ross, not having the legal power to determine who would perform the internal piping for heating and cooling units in the Norwegian Home, was a neutral in that dispute.
*232II
Our two earlier opinions rejecting the Board’s right to control test were guided by the teaching of the Supreme Court in National Woodwork, supra. Affirming the Board, the National Woodwork Court held that a work preservation
clause in a collective bargaining agreement does not violate Section 8(e) of the National Labor Relations Act, 29 U.S.C. § 158(e) (1970),10 and that a carpentry union’s refusal to install prefabricated doors pursuant to such a clause is primary activity that does not violate Sec*233tion 8(b)(4)(B) when the union’s sole objective is preservation of work which its member employees had traditionally performed. The Court traced the evolution of Sections 8(b)(4)(B) and 8(e) and determined that the sweeping language of these sections had to be qualified by the congressional intent, now expressed in the proviso to Section 8(b)(4)(B), to permit coercive union activity which had traditionally been considered primary rather than secondary.11 Recognizing that the critical distinction between secondary and primary activity would often be a subtle and difficult one to make, the Court concluded that the determination whether the carpentry union’s refusal to install the premachined doors was protected primary activity would turn on an “inquiry into whether, under all the surrounding circumstances, the Union’s objective was preservation of work for [the struck employer’s] employees, or whether the agreements and boycott were tactically calculated to satisfy union objectives elsewhere. * * * The touchstone is whether the agreement or its maintenance is addressed to the labor relations of the contracting [struck] employer vis-a-vis his own employees.”12 The Supreme Court found that the Board had appropriately applied this test for distinguishing primary from secondary activity since the Board had ascertained on the basis of substantial evidence that the carpentry union’s refusal to install the prefabricated doors “related solely to the preservation of the traditional tasks of the jobsite carpenters.”13
As we recognized in Local 742, supra, and Local 636, supra, the National Woodwork Court explicitly noted that it was not presented with the question of the propriety of the Board’s right to control doctrine since the struck employer in that case was a general contractor who had the legal power to determine who performed the work the union desired to preserve.14 We nevertheless held, as have all but one of our sister circuits that have faced the issue,15 that the rea*234soning underlying the National Woodwork decision compels the conclusion that an employer’s lack of legal control over the work the union seeks to preserve for its members cannot alone be decisive of the legality of the union’s objectives.16 Indeed, we remain convinced that, absent other evidence that a work preservation strike is actually intended to satisfy illegal secondary objectives, such a strike is lawful primary activity, protected under Sections 7 and 13 of the National Labor Relations Act, 29 U.S.C. §§ 157, 163 (1970),17 as well as under the proviso to Section 8(b)(4)(B).
A.
In validating work preservation clauses, the National Woodwork Court placed primary reliance on the legislative history of Sections 8(b)(4)(B) and 8(e). The Court determined that Congress only intended these sections to prohibit coercive union activity that is directly exerted against an “unconcerned”18 or “neutral” 19 employer, drawn by the union’s activities into “disputes not his own.”20 Section 8(b)(4)(B) was seen as an accommodation between the “dual congressional objectives of preserving the right of labor organizations to bring pressure to bear on offending employers in primary labor disputes and of shielding unoffending employers and others from pressures in controversies not their own.”21 The Board acknowledges that the neutrality of the employer against whom pressure is directly exerted is critical to the distinction between primary and secondary activity.22 It nevertheless comes to the remarkable conclusion that an employer like Hudik-Ross, which is struck by its own employees for the purpose of enforcement of a clause in its collective bargaining agreement with these employees which preserves work which the employees have traditionally performed, is the type of innocent neutral which the Supreme Court says Section 8(b)(4)(B) was fashioned to protect. We cannot agree with the Board’s portrayal.
To assert that Hudik-Ross is a neutral bystander innocently caught up *235in the union’s attempts to achieve its objectives by changing Austin’s policy of purchasing prefabricated climate control units is to ignore the realities of this labor conflict and the process by which Hudik-Ross was confronted with conflicting contractual commitments. The Hudik-Ross management did not innocently awake one day to find itself in the midst of this dispute. The management had negotiated, presumably in good faith, a collective bargaining agreement which obligated Hudik-Ross to preserve for its employees the work of cutting and threading internal piping on the climate control units which these employees were to install. When the management subsequently executed a contract with Austin which it was fully aware would require its employees to install units on which these employees had not done the internal piping, it could hardly have expected the employees to acquiesce in the blatant violation of their contractual rights.23 As we emphasized in Local 742, supra, “The legal effect of the Board’s test is to allow an employer to bind his own hands and thereby immunize himself from union pressure occasioned by his employees’ loss of work. In one act, the employer helps to create a labor conflict and simultaneously wash his hands of it.”24 Hudik-Ross could have totally avoided the labor dispute merely by honoring its bargaining agreement and not bidding on a contract which required it to breach the valid work preservation provision it had negotiated with the union.25 Thus, to accept *236the Board’s characterization of HudikRoss as a neutral bystander under these circumstances would allow the “Cinderella-like transformation of an obviously in*237volved party,” 26 and would both render nugatory the commitment which HudikRoss made27 and demean the collective bargaining process which is the cornerstone of labor relations in the United States.28
The Board insists on closing its eyes to the circumstances surrounding the creation of this labor dispute, circumstances which belie the assertion that HudikRoss is a neutral caught between the contending forces really involved in the work preservation controversy.29 In*238stead, it reasons that, since “[the subcontractor] had no past, present, or future authority to award this work to the Respondents, their actions here must have been undertaken to produce their effect elsewhere,”30 and thus must violate Section 8(b)(4)(B).31 From the premise that it is “reasonable to hold that the object of the union was not an impossible act but was the alternative possible,”32 the Board reaches what it considers to be an ineluctable conclusion that “where the pressured employer cannot himself accede to the union’s wishes, the pressure is secondary because it is undertaken for its effect elsewhere.”33 But rhetoric and rationalization are no substitute for substantial evidence. Even ignoring Hudik-Ross’ actions in initially bidding on the subcontract, the fallacy of the *239Board’s conclusion is readily apparent. For even if one focuses narrowly on the point in time when Hudik-Ross had already executed its second contract, one can clearly see that it was possible for Hudik-Ross to settle the labor dispute which it had created. The record is void of any suggestion that Hudik-Ross attempted to negotiate a compromise with the union under which the union would have agreed to install the climate control units in exchange for extra pay or other special benefits.34 If the Board’s finding that the union’s purpose in refusing to install the units was work preservation was correct, it can be assumed that the union would have accepted a payment from Hudik-Ross to the employees to compensate them at least in part for the employer’s breach of the bargaining agreement. Unions presumably seek agreements to preserve for their members the work which they have traditionally performed in order to maintain the income level of the members. Evidence that the union was unwilling to permit its members to install the prefabricated units even if they were paid for the work they lost by the prefabrication would call into question the Board’s finding that the union’s objective was merely work preservation; it would suggest *240that the union desired to boycott Slant/Fin’s goods for some other reason, such as that firm’s labor relations policies. However, such evidence was not adduced and, given the Board’s finding that the union’s purpose was work preservation, we cannot speculate as to its existence.35
Of course, Hudik-Ross might prefer to terminate its subcontract with Austin or pressure Austin to change its specifications for premachined climate control units rather than to negotiate with its employees as to alternatives for compensating them for their lost work. However, the fact that such a decision might have adverse effects on other employers like Austin and Slant/Fin does not transform an involved employer like Hudik-Ross against whom pressure is exerted into an innocent neutral.36 For as the National Woodwork Court teaches, in enacting the proviso to Section 8(b)(4)(B) Congress made it clear that even a strike which would inevitably have an adverse impact on a secondary employer, like the National Woodwork Association member in that case who had contracted to sell prefabricated *241doors, is not proscribed by Section 8(b)(4)(B) if the employer struck is not an innocent neutral to the union’s dispute.37
The Board’s right to control doctrine is a continuing attempt to circumvent the congressional proviso and is inconsistent with the Court’s analysis in National Woodwork. Moreover, it is a continuing inducement for employers to violate their bargaining agreements. If employers do not want work preservation clauses to cover prefabricated units, they should not sign bargaining agreements with such clauses unless they so state. And when an employer gets himself into a bind, as did Hudik-Ross, he should arbitrate or negotiate his way out. Having the Board bail him out is to demean the National Labor Relations Act by encouraging deliberate, if not always planned, violations of bargaining agreements.38
*242B.
In its brief to this court, the Board vigorously asserts that NLRB v. Denver Bldg. & Constr. Trades Council, 341 U.S. 675, 71 S.Ct. 943, 95 L.Ed. 1234 (1951), mandates a different conclusion than the one we have reached. We find that this reliance on Denver is misplaced. The Denver Court sustained a Board finding that a construction union had violated Section 8(b)(4)(B) by striking against a general contractor in order to force him to terminate his contract with a subcontractor who employed nonunion labor — a classic secondary boycott. In the course of its opinion the Denver Court in dicta made several statements which the Board in its brief now maintains establish principles upon which the right to control test can be based:
If there had been no contract between Doose & Lintner [the general contractor] and Gould & Preisner [the nonunion subcontractor] there might be substance in [the union employees’] contention that the dispute involved no boycott. If, for example, Doose & Lintner had been doing all the electrical work on this project through its own nonunion employees, it could have replaced them with union men and thus disposed of the dispute. However, the existence of the Gould & Preisner subcontract presented a materially different situation. The nonunion employees were employees of Gould & Preisner. The only way that respondents [the union employees] could attain their purpose was to force Gould & Preisner itself off the job. This, in turn, could be done only through Doose & Lintner’s termination of Gould & Preisner’s subcontract. The result is that, the Council’s strike, in order to attain its ultimate purpose [full unionization of the construction site], must have included among its objects that of forcing Doose & Lintner to terminate that subcontract. * * * It is not necessary to find that the sole object of the strike was that of forcing the contractor to terminate the subcontractor’s contract.
341 U.S. at 688 — 89, 71 S.Ct. at 951, quoted in brief for the NLRB at 8 — 9 (emphasis in original). Although this language obviously does not constitute a holding endorsing the Board’s right to control doctrine since the general contractor in Denver had full legal power to assign the work which the union did not want nonunion employees to perform, the Board argues that this language should be applied in the instant case. The union’s ultimate objective of work preservation, the argument runs, could only be attained by keeping Slant/Fin from completing the internal piping; this, in turn, could be done only through Austin’s termination of its contract with Slant/Fin; the union’s refusal to install the units must therefore have included among its objects that of forcing Austin to terminate the Slant/Fin contract; and such an objective would, given the dicta from the Denver opinion, render the refusal to install the units an illegal secondary boycott under Section 8(b)(4)(B).
As we have already indicated, we do not agree that termination of the Slant/Fin contract was a necessary intermediate step to satisfaction of the union’s ultimate objective; Hudik-Ross could have resolved the dispute without *243affecting the contractual relationships of either Austin or Slant/Fin. But even accepting the factual premises of the Board’s analysis, the quoted Denver language does not support the Board’s right to control test. For a literal application of that language would have outlawed even the union activity in National Woodwork, where the struck employer was a general contractor with full legal control over assignment of the work in dispute. In National Woodwork the carpentry union’s objective of work preservation was only obtained by the general contractor’s termination of his contract to purchase prefabricated doors from one of the Woodwork Association’s members. But the National Woodwork Court, in upholding the union’s actions, clearly did not consider this to be a proscribed secondary objective; indeed, that Court did not find it necessary to even consider the quoted Denver language.39
A closer examination of the Denver opinion reveals why that case was inapposite to both National Woodwork and the present case. The Board’s quotation of Denver is less than candid, and reveals the danger of reducing a complex analysis turning upon “all the surrounding circumstances” into a simplistic per se doctrine. For the above paragraph from Denver was introduced by this observation:
In the background of the instant case there was a longstanding labor dispute between the Council and Gould & Preisner due to the latter’s practice of employing nonunion workmen on construction jobs in Denver.
341 U.S. at 688, 71 S.Ct. at 951. The Court, looking to the whole factual context of the controversy, thus recognized that the union pressure was directed against the labor relations practices of the subcontractor, and that the strike against the general contractor was “tactically calculated to satisfy union objectives elsewhere.”40 In National Woodwork, as in our case, there was no indication that the substance of the dispute was with a third party. Given National Woodwork and the 1959 proviso added to § 8(b)(4)(B), the mere fact that the primary employer, in order to settle the dispute between himself and his employees concerning his “labor relations * * * vis-á-vis his own employees,” 41 might be forced to terminate his contract with such a third party cannot alter this conclusion.42
Ill
We do not think that an employer who is struck by his own employees for the purpose of requiring him to do what he has lawfully contracted to do to benefit those employees can ever be considered a neutral bystander in a dispute not his own.43 We recognize, of course, that a strike may have more than a single objective and may thus violate Section 8(b)(4)(B) if even one objective is a prohibited secondary one.44 However, *244we hold that in situations such as the present one, where there is a valid work preservation provision in a collective bargaining agreement and where a union refuses to acquiesce in an employer’s violation of that agreement, it is reasonable to assume that the employer can comply in accordance with his prior commitment to his workers and that, absent more evidence than mere stoppage of work, the union’s objectives are legitimate and the refusal to install the prefabricated materials is lawful.
We therefore conclude that in this case, as in National Woodwork, the union’s refusal to install the prefabricated components must be deemed primary concerted activity hot prohibited by Section 8(b)(4)(B) if it is determined, “under all the surrounding circumstances,” 45 that the sole objective of the union was to preserve for employees of the struck employer work they traditionally performed. Since the Board here found that the union’s purpose was to preserve work which Hudik-Ross’ employees had traditionally performed, and there is no substantial evidence, as distinguished from the Board’s rationalizations, in this record that the union’s purpose was also “to satisfy union objectives elsewhere,” the Board’s decision holding the union guilty of a Section 8(b)(4)(B) violation may not stand. However, in remanding in Local 742, supra, and Local 636, supra, we held that legal control in the struck employer over assignment of the work *245which a union professes a desire to preserve, while not alone dispositive, may be considered by the Board along with other factors suggested by the National Woodwork Court in determining the union’s actual objective. In remanding here to give the Board an opportunity to reconsider its ruling in this case,46 we emphasize at the risk of repetition that the Board is not free to focus on HudikRoss’ lack of control to the total exclusion of the circumstances which the National Woodwork Court stated might be relevant to the inquiry into the union’s objective.47 The Board may fashion its own formulations as to the relevance of certain facts to National Woodwork’s test for distinguishing primary from secondary activity. But as we held in Local 742, supra, and Local 636, supra, the Board may not transform that test, directly dr indirectly, into a vehicle for subverting the congressional purpose by focusing on only one among many potentially relevant factors.
Remanded for further proceedings.
.Section 8(b)(4)(B), 29 U.S.C. § 158(b)(4)(B) (1970), provides:
(b) It shall be an unfair labor practice for a labor organization or its agents — ■ ******
(4)(i) to engage in, or to induce or encourage any individual employed by any person engaged in commerce or in an industry affecting commerce to engage in, a strike or a refusal in the course of his employment to use, manufacture, process, transport, or otherwise handle or work on any goods, articles, materials, or commodities or to perform any services; or (ii) to threaten, coerce, or restrain any person engaged in commerce or in an industry .affecting commerce, where in either case an object thereof is—
* * * * * *
(B) forcing or requiring any person to cease using, selling, handling, transporting, or otherwise dealing in the products of any other producer, processor, or manufacturer, or to cease doing business with any other person, or forcing or requiring any other employer to recognize or bargain with a labor organization as the representative of his employees unless such labor organization has been certified as the representative of such employees under the provisions of section 159 of this title: Provided, That nothing contained in this clause (B) shall be construed to make unlawful, where not otherwise unlawful, any primary strike or primary picketing!.]
. Joint Appendix at 254.
. See NLRB v. Local 164, IBEW, 388 F.2d 105, 107-10 (3d Cir. 1968); American Boiler Mfrs. Assn. v. NLRB, 404 F.2d 556, 561 (8th Cir. 1968); Beacon Castle Square Bldg. Corp. v. NLRB, 406 F.2d 188, 192 n.10 (1st Cir. 1969) *229(dictum); Western Monolithics Concrete Products, Inc. v. NLRB, 446 F.2d 522, 526 (9th Cir. 1971). The Second Circuit has also employed an analysis of § 8(b)(4)(B) which is inconsistent with the right to control doctrine. NLRB v. Local No. 28, Sheet Metal Workers, 380 F.2d 827, 830 (1967). See also Danielson v. Painters Dist. Council No. 20, 305 F.Supp. 1108, 1113-17 (S.D.N.Y. 1969) (dictum) (denying § 10(1) preliminary injunction). Law review commentators have also been critical of the right to control test. See, e. g., Lesnick, Job Security and Secondary Boycotts: The Reach of NLRA §§ 8(b)(4) and 8(e), 113 U.Pa. L.Rev. 1000, 1036-39 (1965); Note, 77 Yale L.J. 1401, 1416 (1968) (“The modem primary-secondary analysis requires the complete abandonment of the present ‘right to control’ rule.”).
Recently a panel of Ninth Circuit judges approved the Board’s right to control test in dictum. See Associated General Contractors of California, Inc. v. NLRB, 514 F.2d 433 (decided March 28, 1975), vacating 207 NLRB No. 58 (1973). Although professing that a subcontractor’s right to control is merely an “important factor” in assessing “all the surrounding circumstances” of a labor dispute, the Associated General Contractors court in effect asserted that a single, sufficient criterion for finding that a subcontractor is a “neutral, unoffending employer” is the fact that it “did not have and never had the power to accede to the union’s demands.” Id., 514 F.2d at 437. See also, e. g., id. at 438 (“A union’s right to enforce a work preservation clause against an employer may extend only to work which is his to assign. When it is applied to work beyond the employer’s power to give, a work preservation clause necessarily embodies a prohibited secondary objective.”). This is, in actuality, the per se right to control test. See note 9 infra. It is curious that in making these statements the Ninth Circuit panel acknowledged neither a contrary precedent in the Ninth Circuit, see Western Monolithics, supra, nor the analysis and holdings (or the existence) of contrary cases in four other circuits. Moreover, in basing its holding on the rationale that in such situations the union is seeking to acquire rather than to preserve work, the court manifested a misunderstanding of the nature of work preservation agreements. See, e. g., 172 U.S.App.D.C. pp. 238-240, 521 F.2d pp. 898-900 & notes 25', '34, & 37 infra.
. See Local 438, Plumbers & Pipe Fitters, 201 NLRB 59, enforced sub nom. George Koch Sons, Inc. v. NLRB, 490 F.2d 323 (4th Cir. 1973). Unlike its earlier right to control opinions, in its Koch opinion the Board does say it is applying the “all the surrounding circumstances” test required by National Woodwork and all the Circuit Courts that have considered the question. But a mere reading of the Board’s opinion demonstrates that its application of the National Woodwork test is pro for-ma and that its own right to control test is determinative. See also note 9 infra.
. JA at 253.
. Id. at 234.
. See id. at 236.
. Id. at 254.
. Since the right to control doctrine had been rejected by five circuits, the Board understandably did not mention that doctrine by name. Rather, after noting the union’s work preservation purpose, the Board merely cited its Koch opinion and stated that “Hudik was incapable of assigning its employees this work; such work was never Hudik’s to assign in the first place.” Id. See also note 36 infra. In its brief to this court the Board admits that it is applying the right to control doctrine, but characterizes the test as merely creating a ‘‘prima facie" inference that there is an illegal secondary objective, “absent proof to the contrary.” Brief for the NLRB at 5. We realize that under SEC v. Chenery Corp., 318 U.S. 80, 93-95, 63 S.Ct. 454, 87 L.Ed. 626 (1943), we review the Board’s opinions and not its counsel’s brief. However, since counsel’s rationalization might be adopted by the Board in its next right to control case, we deem it useful, in the interest of bringing right to control litigation to an early conclusion, to comment on it. In short, we find that, given the virtual impossibility of proving the lack of the imputed secondary objective, this “prima facie" approach in effect constitutes the same old per se test which we have condemned in our prior opinions and which contravenes the rationale and spirit of National Woodwork. See, 172 U.S.App.D.C. pp. 232-241, 521 F.2d pp. 892-901, infra.
Our conclusion that Hudik-Ross is far from being an innocent neutral bystander to the dispute over installation of the prefabricated units does not depend at all on any suspicion that Hudik-Ross instigated Austin’s decision to use the Slant/Fin units. Cf. Painters Dist. Council No. 20, 185 NLRB 930, 932 (1970). We fully accept the Board’s factual finding that Hudik-Ross merely bid on a job for which Austin had already specified the Slant/Fin units. Rather, our conclusions are based on an analysis of all the surrounding circumstances of the conflict, not just the circumstances relating to the locus of actual power to assign the work. By contrast, once the Board finds that the employer lacked legal control, it finds a per se violation of § 8(b)(4)(B). See generally Local 438, Plumbers & Pipe Fitters, supra note 4. As we stated in Local 742, Carpenters v. NLRB, 144 U.S.App.D.C. 20, 24, 444 F.2d 895, 899 (1971):
The artificiality of the [Board’s right to control] test is particularly patent in cases such as this one — where the employees apparently have a grievance growing out of labor relations with their own employer (i. *231e., loss of traditional unit work) and immediately provoked by an action of their own employer (i. e., his signing of a contract which would deprive them of that work). The Board does not stop to consider these aspects of the dispute. Nor does it look to see whether there may be other grievances, against other employers, which underlie the union’s action. Rather, the Board seems to hold that, when an employer contracts away his power to satisfy union demands, he also contracts away his interest and involvement in the labor relations issue in dispute. He is depicted as the mere passive agent of others * * * ; the fact that the present dispute has its origin and its substantive focus in his ongoing labor relations with his employees is deemed irrelevant. * * *
(Footnote omitted.)
In attempting to rationalize and affirm the Board’s holding, the dissenters present a smorgasbord of possible explanations of what the Board has done. But see dissenting op. at n.72. First, we are offered the per se right to control test in its purest form:
Hudik is essentially neutral in this dispute because it does not have and never did have the power to comply with the Steamfitters’ demands. Thus the pressure created by the Hudik employees’ boycott of the Slant/Fin units must have been directed at Austin and Slant/Fin as they were the only parties with the power to satisfy the demand that the work be taken from Slant/Fin employees and reassigned to the Union.
Id. at 172 U.S.App.D.C. 260, 521 F.2d at 920 (emphasis added). See also id. at 261, 521 F.2d at 921 (“The Union is seeking what it asserts is work preservation, but the means it has chosen toward that end — a strike against an employer who never had the disputed work to assign — constitutes secondary pressure.”) (emphasis in original); id. 172 U.S.App.D.C. at 266, 521 F.2d at 926 (“Even where right to control is not decisive, in almost any case it will be a factor entitled to very substantial weight because it measures the ability of the employer to comply with the union demands.”); id. 172 U.S.App.D.C. at 268, 521 F.2d at 928 (“boycotts by craft unions against subcontractors necessarily have as a primary object the application of pressure to those third parties who actually require the use of factory-prepared products”) (emphasis added); id. at n.53 (“[Ojnly Austin and Slant/Fin are capable of acceding to the Union’s demands. Thus Hudik is neutral with respect to the particular remedy of economic action which the Union invoked to redress its grievances.”); id. 172 U.S.App.DX3. at 278, 521 F.2d at 938 & n.101. But see id. ¿t n.44.
Next, we are told that the Board has applied a prima facie test because it will validate a work preservation action against a subcontractor who possessed the legal right to control the work assignment but contracted away that right:
The Board does not employ a per se formulation, which might well violate the stricture of National Woodwork that the focus of a union’s action must be determined from all the surrounding circumstances; instead, the Board'relies on a prima facie standard. By this test, a union may not boycott an employer who lacks the right to control the assignment of disputed work, provided that the employer has not voluntarily relinquished that control. The redeeming feature of this criterion is that it permits and even mandates the conclusion that the union acted properly in launching an economic action whenever “the employer’s loss of power to assign the work is the result of his own efforts to instigate the subcontracting to another of work subject to his work preservation agreement with the union” * * *. In such a case the employer would cease to be ’ neutral, and would be termed “offending” by virtue of his voluntary action surrendering legal control of the disputed work.
Dissenting op., 172 U.S.App.D.C. at 271, 521 F.2d at 931 (footnotes omitted; emphasis in original).- See also id. 172 U.S.App.D.C. at 277, 521 F.2d at 937 (“the prima facie right-to-control test rests on the Board’s considered judgment that a subcontractor’s inability to affect or avoid prefabrication speciñcations in general contracts renders him an inappropriate and impermissible target of union economic activity”) (emphasis added). This is the approach of the Board as elaborated in Koch, and which, as we have indicated above, is a per se test once the actual locus of legal control is isolated; the Board does not consider other circumstances to determine whether the employer without control over the work itself is nevertheless not a neutral in the labor dispute.
Finally, the dissent asserts that the Board, in conformity with the National Woodwork decision, actually evaluated “all the surrounding circumstances” to determine whether HudikRoss was a neutral; the Board, under this rationalization, did not simply label Hudik-Ross a neutral party once the Board concluded it did not have, and never had, the legal power to assign its employees the disputed work. See, e. g., dissenting op., 172 U.S.App.D.C. at 257-258, 265-266, 268-269, 519 F.2d *232at 917-918, 925-926, 928-929, 941, & nn.8, 74. The dissent premises this explanation on the fact that the ALJ, in another context, used the phrase “all the surrounding circumstances,” and the fact that the Board affirmed his “rulings, findings, and conclusions” to the extent they were consistent with its decision. See, e. g., id. 172 U.S.App.D.C. at 265-266, 521 F.2d at 925-926 & n.8. Based on this slender reed, we are implored to discount the fact that the Board, in citing Koch as the basis for its decision, was following its right to control test as fully enunciated in that case. The dissent wisely omits the Board’s citation of Koch and similar cases in its otherwise extensive quotation from the Board’s decision, see id. at n.10, and it is clear that both the ALJ and the Board simply categorized Hudik-Ross as a neutral because it lacked control over the assignment of the disputed work. Indeed, the ALJ concluded:
While it is true that there are conflicting interpretations of the National Woodwork decision, supra, I believe that under the Board’s view of the law the Respondent herein has violated section 8 (b) (4) (i) (ii) (B) of the Act since Hudik was a secondary employer that, unlike Frouge in the National Woodwork case, had no control over the selection and specification of the prepiped units. * * *
JA at 242 (emphasis added). Moreover, the cases cited and discussed by the ALJ, see JA at 237, 242 n.13, are all ones in which the Board determined that the locus of control over the work in dispute was conclusive as to the question of the legality of the union’s activity.
Nevertheless, it is true that the ALJ employed the phrase “surrounding circumstances” in the hypotheticals quoted by the dissent, see dissenting op. at n.8, and the dissenters dwell at considerable length on the circumstance to which the ALJ referred — the extent to which the construction industry in major metropolitan areas is unionized. See, e. g., id. 172 U.S.App.D.C. at 268-270, 521 F.2d at 928-930. However, the ALJ simply referred to that factor as a circumstance which he believed made Hudik-Ross an effective instrumentality of pressure against Austin and Slant/Fin. See id. at n.8. Even the ALJ recognized that this factor (effectiveness or ineffectiveness of secondary pressure) is absolutely irrelevant to the question of whether HudikRoss was a neutral in the labor dispute and thus immune even from threats of secondary pressures under § 8(b)(4)(B). See id. (“the fact that in Example A * * * Hudik would be an ineffective means of pressure by the Union against Slant/Fin and Austin, and, in Example B, the instant case, Hudik is an effective means of pressure in view of all the surrounding circumstances, does not alter the fact that in both situations, Hudik is a means or instrumentality and that the Union’s primary dispute is with Slant/Fin and Austin”). But see dissenting op. at n.55. Thus the ALJ’s use of that phrase (as part of an argument that Hudik could not comply with the union’s demands) in no way discredits our conviction that both the ALJ and the Board are continuing to apply an impermissible per se right to control test. Moreover, as we elucidate more fully later in our opinion, both the ALJ and the Board are incorrect in the premises which underlie both the right to control test and the hypotheticals the dissent quotes; Hudik is not a neutral in this labor dispute, see generally pp. 172 U.S.App.D.C. 261-268, 521 F.2d pp. 921-928, infra, and it may comply with the union’s demands, even without ceasing doing business with Austin and Slant/Fin or attempting to force them to change their business practices, see, e. g., pp. 172 U.S.App.D.C. 264-268, 521 F.2d pp. 924-928, infra.
. Except for those agreements specified in the proviso to § 8(e), that section renders void and unenforceable an employer’s agreement to do that which § 8(b)(4)(B) prevents the union from exerting pressure to bring about. See note 38 infra.
The language of § 8(e) is comparable to the language of § 8(b)(4)(B) in most significant respects:
(e) It shall be an unfair labor practice for any labor organization and any employer to enter into any contract or agreement, express or implied, whereby such employer ceases or refrains or agrees to cease or refrain from handling, using, selling, transporting or otherwise dealing in any of the products of any other employer, or to cease doing business with any other person, and any contract or agreement entered into heretofore or hereafter containing such an agreement shall be to such extent unenforcible [sic] and void[.] * * *
. In 1959, a proviso was added to § 8(b)(4)(B), explicitly exempting primary activity from the prohibitions of that section:
Provided, That nothing contained in this clause (B) shall be construed to make unlawful, where not otherwise unlawful, any primary strike or primary picketing[.]
The National Woodwork Court held that, in light of congressional intent, the same limitation was implicitly incorporated into § 8(e). See note 38 infra.
. 386 U.S. at 644-45, 87 S.Ct. at 1268 (emphasis added; footnotes omitted). In a companion case, Houston Insulation Contractors Assn. v. NLRB, 386 U.S. 664, 668, 87 S.Ct. 1278, 1281, 18 L.Ed.2d 389 (1967), this language was reaffirmed. “National Woodwork Mfrs., supra, holds that collective activity by employees of the primary employer, the object of which is to affect the labor policies of that primary employer, and not engaged in for its effect elsewhere, is protected primary activity.”
. 386 U.S. at 646, 87 S.Ct. at 1268.
. See id. 386 U.S. at 616-17 n.3, 87 S.Ct. 1250. Much of the argumentation in the briefs to the Court in National Woodwork concerned the propriety of upholding the union’s actions because the employer had control of the work. Indeed, the Board felt compelled to assert that even if the Court might conclude that the Board and the court below placed undue emphasis on the fact that Frouge had “control” over the kind of doors he could use * * * the result reached * * * is nevertheless proper.
Brief for the NLRB at 7. Rather than base its holding on the extent of employer control, the Supreme Court engaged in a detailed factual examination of “all the surrounding circumstances” of the dispute. Seen from this perspective, its “reservation” of the control question is better understood as a warning that the opinion not be read as impliedly approving the Board’s right to control doctrine. In resolving the right to control problem, we now follow the lead of the Supreme Court in determining, on all the factors presented, whether the union’s goal is solely work preservation and whether the struck employer is a neutral to the dispute.
.See note 3 supra. Even the Fourth Circuit, in approving the Board’s right to control test, was at pains to conclude that in finding a violation the Board had looked to “all the surrounding circumstances,” as required by National Woodwork. See Koch, supra note 4, 490 F.2d at 327. However, the Board in that case found the subcontractor’s lack of control determinative of the legality of the union’s conduct, see 201 NLRB at 61; all of the “surrounding circumstances” supplied by the *234Fourth Circuit in its opinion were merely alternative ways of describing that fact. See 490 F.2d at 327.
. While the employer’s lack of legal control cannot be determinative, it may still be considered by the Board as part of its inquiry into the union’s actual objectives. See Local 742, Carpenters v. NLRB, supra note 9, 144 U.S.App.D.C. at 28, 444 F.2d at 903; Local 636, Plumbers & Pipefitters v. NLRB, 139 U.S.App.D.C. 165, 169-70, 430 F.2d 906, 910-11 (1970). See also 172, U.S.App.D.C. pp. 243-245, 521 F.2d pp. 903-905, infra.
. These sections preserve the right of employees to strike and to engage in other concerted activities for the purpose of mutual aid or protection. The National Woodwork Court stated that, in “the absence of clear indicia of congressional intent to the contrary, these provisions caution against reading statutory prohibitions as embracing employee activities to pressure their own employers into improving the employees’ wages, hours, and working conditions.” 386 U.S. at 643, 87 S.Ct. at 1268.
. Id., 386 U.S. at 624, 87 S.Ct. 1250.
. Id. at 623, 632, 87 S.Ct. 1250.
. Id. at 620, 626, 87 S.Ct. 1250.
. Id. at 626-27, 87 S.Ct. at 1259 quoting NLRB v. Denver Bldg. & Constr. Trades Council, 341 U.S. 675, 692, 71 S.Ct. 943, 95 L.Ed. 1284 (1951). The dissenting judges delve into the legislative history of §§ 8(b)(4)(B) and 8(e) to prove that Congress was particularly concerned with installation abuses and thereby to prove that the refusal to install the prepiped units was illegal secondary activity. See, e. g., dissenting op., at 172 U.S.App.D.C. at 262-265, 521 F.2d at 922-925. However, the National Woodwork Court has already thoroughly canvassed this legislative history, see generally 386 U.S. at 620-44, 87 S.Ct. 1250, and has concluded ,that the refusal to install prefabricated products is proper if the pressure is exerted against an employer who is not a neutral in the dispute. Merely characterizing the controversy as one involving purported installation abuses (and generally in the context of union action initiated with the objective of expanding the union’s representational jurisdiction, see e. g., dissenting op., 172 U.S.App.D.C. at 263-264, 521 F.2d at 923-924) does not lead to the delphic conclusion that the pressure in this case is tainted secondary activity.
.Local 438, Plumbers & Pipe Fitters, 201 NLRB 59, 61 (1973); brief for the NLRB at 5. See also, e. g., dissenting op., 172 U.S.App. D.C. at 262, 521 F.2d at 922.
.Indeed, the terms of the collective bargaining agreement itself provide internal indicia that Hudik-Ross is not a neutral to this dispute. Article One of that agreement specifies that both parties are to abide by certain rules governing wages, hours, “and other conditions of employment.” JA at 210. Rule IX is among those to which both sides agreed to be bound. JA at 213. Article Two of the agreement then stipulates that strikes or lockouts are to be prohibited, but only “so long as this agreement and the rules hereto attached are conformed to by both parties.” JA at 210 (emphasis added). Hudik-Ross must therefore have realized that it had contractually acknowledged the union’s right to strike in the situation presented to us. Indeed, it is curious that Hudik-Ross, the “neutral” that was supposedly injured by being dragged into a “labor dispute not its own,” did not file the charge of an unfair labor practice; rather, it was filed by the general contractor, Austin. Perhaps Hudik-Ross perceived the injustice that would result if it attempted to have the Board directly rectify Hudik-Ross’ breach of contract; perhaps it merely sought to avoid the exacerbation of labor relations that would result by adding this insult to the injury it had previously inflicted on the union. We appreciate the fact that a contractual provision cannot immunize either an employer or a union from an unfair labor practice charge. See, e. g., Radio Officers’ Union v. NLRB, 347 U.S. 17, 74 S.Ct. 323, 98 L.Ed. 455 (1954). . However, we see no justification for converting this dispute over enforcement of a valid contractual provision, in which the union lawfully strikes in accordance with an explicit bargaining clause, into an unfair labor practice proceeding before the Board.
. Local 742, Carpenters v. NLRB, supra note 9, 144 U.S.App.D.C. at 24, 444 F.2d at 899.
. We do not believe that this restriction unduly ties an employer’s hands concerning managerial decisions. Hudik-Ross could have, and still can, negotiate collective bargaining agreements which exempt from the work preservation clause work over which it does not have legal control. Indeed, on remand the Board is free to reconsider whether the parties to the agreement actually intended the cutting, threading, and installation of the internal piping of the climate control units to fall within its scope in the situation here presented. The dissent implies that the ALJ has already made a finding that the parties to the bargaining agreement did not so intend, and that the Board implicitly upheld this finding. See, e. g„ dissenting op., 172 U.S.App.D.C. at 267-268, 280, 521 F.2d at 927-928, 940, & nn.71 & 106. However, the dissent recognizes that the ALJ declined to rely on his “opinion” that Rule IX “necessarily implied that it referred to pipe within Hudik’s control,” see JA at 237. Dissenting op. at n.7. In any event, the ALJ’s “opinion” appears to be premised on his views of the ultimate merits of the right to control doctrine rather than on any expertise in interpreting collective bargaining agreements, and would appear to be contradicted by the plain language of the agreement, which stipulates that “[rjadiator branches, convector branches and coil connectors shall be cut and threaded by hand on the job * * * JA at 233 (emphasis added). The Board accepted the fact that the work stoppage was motivated by the desire to preserve traditional unit work, and we therefore do not believe it accepted any finding (to the extent one may have been *236made) that this work was not intended to be included within the ambit of Rule IX. See also text appended to dissenting op. Figure 1. In any event, custom and tradition in the industry must also be looked to in determining the intent of the parties with respect to what work is to be preserved, even in the absence of an explicit work preservation provision. See Local 742, Carpenters v. NLRB, supra note 9, 144 U.S.App.D.C. at 24, 444 F.2d at 899. Moreover, given the record now before us, when the Board on remand analyzes “not only the situation the pressured employer finds himself in but also how he came to be in that situation,” in order to determine whether he is an “unoffending party,” see Local 438, Plumbers & Pipe Fitters, supra note 4, 201 NLRB at 64, it must consider whether Hudik-Ross knowingly entered the second contract in contravention of the prior one.
It is important to recognize that Hudik-Ross’ refusal to bid on the Austin contract, in compliance with its collective bargaining agreement, would indeed serve work preservation goals. This point is often misunderstood. For example, the ALJ in this case asked rhetorically: “[I]f Hudik, an employer of union steamfitters, does not bid on jobs and does not secure subcontracts, how does such a situation preserve or increase work for Hudik’s union steamfitters[?]” JA at 240. Yet he had unknowingly answered that question himself earlier in his opinion: “If prepaid [sic] units cannot be installed * * * Austin and other engineers and general contractors will not specify their purchase and use in buildings.” JA at 239. The union certainly expected the work preservation clause to be complied with. Like the ALJ, it knew such clauses would in fact subserve its legitimate end of ensuring that its members could continue to perform in the future the work they had traditionally performed in the past. Of course, it is also true that Hudik-Ross and similar employers could bid on a subcontract specifying prefabricated products and still satisfy a union’s work preservation goals, but in this latter situation they would probably be subserved by negotiation of a monetary settlement that would partially compensate the employees, for their lost work. See 172 U.S.App.D.C. pp. 238-240, 521 F.2d pp. 898-900 & note 34 infra. It should also be noted that the dissent, apparently oblivious to the fact that Hudik-Ross could take this latter tack, compounds its error by making the statement, which has no support in the record, that “Hudik could not decline to bid on projects with prefabrication specifications and continue to be a competitive subcontractor.” Dissenting op., 172 U.S.App.D.C. at 268, 521 F.2d at 928. If this were actually the case, one might wonder why Hudik-Ross contractually bound itself to such an allegedly, self-destructive course.
Although the Board rejected the ALJ’s misconception that Rule IX was not designed for work preservation purposes in these circumstances, a similar fallacious belief may lie at the root of its right to control doctrine. In its brief to the Supreme Court in National Woodwork, in supporting its claim that the union had not violated § 8(b)(4)(B), the Board stated:
[T]his provision [in the bargaining agreement in National Woodwork] was a lawful work preservation clause, reflecting the Union’s policy of preserving for jobsite carpenters work which they have performed for over 80 years. Since Frouge had failed to abide by this lawful contract provision, the Union had a legitimate dispute with him; and, since he was not required by any arrangement with the project owner to use pre-cut doors, Frouge was in a position to accede to the Union’s demands without having contract relations severed or even directly affected. Accordingly, by refusing to handle pre-cut doors for Frouge, the Union confined its activity to the employer with whom it had its basic dispute, and its activity was therefore primary.
Brief for the NLRB at 5-6 (emphasis added). If the Board is serious about its characterization of the union/Hudik-Ross provision as a valid work preservation clause, the logic of National Woodwork should mandate a conclusion that the union’s activity in our case is lawful. In both National Woodwork and this case, there was a valid work preservation clause. In both National Woodwork and this case, the employer could comply with the union’s demands before breaking the contract. And, contrary to the Board’s assertion, in both National Woodwork and this case, some third party would inevitably be affected by compliance after the contract was broken. Admittedly, only a manufacturer was involved in National Woodwork, whereas this case involves both a manufacturer and a general contractor. But that cannot obscure the fact that for all relevant analytical purposes the situation of the two employers is identical. See also note 28 infra.
. A final misconception concerning work preservation agreements between subcontractors and unions is that exhibited by the dissent, see, e. g., dissenting op., 172 U.S.App.D.C. at 261-262, 268, 521 F.2d at 921-922, 928, and by the recent panel opinion in the Ninth Circuit, see Associated General Contractors of California, Inc. v. NLRB, supra note 3, 514 F.2d at 435. This misconception involves the belief that when a subcontractor’s employees request that when a construction contract *237specifies prefabricated products the subcontractor either not bid on the contract or else compensate them for their lost work, they are not seeking to preserve traditional work but are. attempting to acquire additional work. However, by the very nature of subcontract bidding, a subcontractor will always be acquiring work when he bids on a project; the characterization of union activity as having a work preservation objective must therefore depend on whether it is the type of unit work which the employees have traditionally performed, not whether they actually performed the particular work in question. And as indicated above, enforcement of a work preservation clause is designed to protect such traditional work whether the subcontract specifications themselves required that the traditional work be replaced by prefabrication or whether the specifications granted to the subcontractor discretion to displace the employees’ traditional work. In both situations the union seeks to prevent elimination of employees’ work through factory prefabrication or, at a minimum, to prevent their employer from lending active support to elimination of that work.
. Local 742, Carpenters v. NLRB, supra note 9, 144 U.S.App.D.C. at 24, 444 F.2d at 899.
. As Judge Lasker observed in a similar situation:
It would be unthinkable to apply the “right to control” test to facts such as those just outlined. To do so would be to encourage subcontractor employers to undermine their collective bargaining agreements by actively soliciting contracts whose very terms called for conduct violative of those trade agreements * * *. Manufacturers and general contractors, too, would be tempted to insert all manner of specification and standard[s] into their licenses and contracts with a total disregard of subcontractors’ commitments to their respective unions.
Danielson v. Painters Dist. Council No. 20, supra note 3, 305 F.Supp. at 1115.
. Cf., e. g., International Union of Electrical Workers v. NLRB, 138 U.S.App.D.C. 249, 255, 426 F.2d 1243, 1249, cert. denied, 400 U.S. 950, 91 S.Ct. 239, 27 L.Ed.2d 256 (1970).
In its brief for respondent NLRB at 26, which it filed in National Woodwork, the Board stated:
[Wjhere, as here, the union is opposed to a product, not because of its price or its design, but because it deprives the employees whom the union represents of work which they have traditionally performed, there is a sufficiently direct connection between the product and employment security to bring the question respecting the use of that product within the area of mandatory bargaining under the Act.
However, in its Koch opinion the Board distinguished National Woodwork and Fibreboard Paper Products Corp. v. NLRB, 379 U.S. 203, 85 S.Ct. 398, 13 L.Ed.2d 233 (1964), from a situation where the employer lacks power to assign the work sought to be preserved:
The situation here is radically different since Phillips never initially had the disputed work and thus obviously could not have contracted away that which it never had and could not have been ordered to bargain over that which it never had.
201 NLRB at 63 n.22. We fail to comprehend the logic of this assertion. Certainly Phillips in that case and Hudik-Ross in our case were free to agree not to execute other contracts which would require them to force their employees to handle prefabricated goods. This is effectively what a work preservation clause requires in the present situation. Although we do not reach the substantial question whether employers could be forced to bargain over such clauses, we find that, having negotiated and agreed to such a clause, Hudik-Ross must abide by it; nothing in the Act or the Supreme Court’s decision in National Woodwork requires that an employer be allowed to escape such a freely-undertaken obligation merely by unilaterally executing subsequent contracts.
.The Board’s holding has the potential for unnecessarily harsh or excessively disruptive results. Although the ALJ found that Austin and Slant/Fin were'the primary employers for purposes of the work preservation dispute with the union, the Board declined to decide whether the union could therefore have exerted direct pressure against them. See JA at 254 n.l. It is thus possible that the Board is prepared to accept the position advanced by amicus curiae Chamber of Commerce of the United States that, unless the target of the strike has both the power to control the work assigned and a bargaining relationship with the union, the union’s economic pressures are illegal secondary activity. In the present case there would thus be no primary employer; indeed, in most subcontracting situations the subcontractor’s employees would be deprived *238of all economic weapons and all legal mechanisms for preserving their traditional work against onrushing technological changes. We do not find it necessary to rule on whether the union could have exerted pressure directly against Austin or Slant/Fin. However, we do note that interpreting § 8(b)(4)(B) so that, in a situation where a union is motivated by a single lawful goal, it is nevertheless adjudged guilty of secondary activity without there being some employer against whom it could have exerted pressure gives the section a harshness which has not heretofore been suggested by its most aggressive proponents. Certainly nothing in § 8(b) compels such a result.
On the other hand, when a union’s sole objective is work preservation, it would be anomalous to allow it to press its demands on a general contractor with whom it has no ongoing relationship. Rather than limit the scope of labor disputes consonant with the congressional intent expressed in § 8(b)(4), such a result is likely to expand them since it would probably affect all subcontractors on a jobsite. The National Woodwork Court tacitly accepted work preservation as a legitimate subject of mandatory collective bargaining, within the “wages, hours, and other terms and conditions of employment” language of §§ 8(d) and 9(a) of the National Labor Relations Act. See 386 U.S. at 642-43, 87 S.Ct. at 1267; note 28 supra. Disputes over such subjects are best resolved within the bargaining unit encompassing the contending parties. See also Connell Constr. Co. v. Plumbers & Steamfitters Local No. 100, 421 U.S. 616, 95 S.Ct. 1830, 44 L.Ed.2d 418 (1975).
Although our holding that the right to control test must be rejected is not based on the above considerations, we find that they shed light on Hudik-Ross’ actual involvement with the subject matter of this labor dispute.
. See Local 438, Plumbers & Pipe Fitters, supra note 4, 201 NLRB at 62.
. See National Woodwork, 386 U.S. at 645, 87 S.Ct. 1250.
. Local 438, Plumbers & Pipe Fitters, supra note 4, 201 NLRB at 62 n.14, quoting Ohio Valley Carpenters Dist. Council v. NLRB, 339 F.2d 142, 145 (6th Cir. 1964).
.201 NLRB at 63. See also George Koch Sons, Inc. v. NLRB, supra note 4, 490 F.2d at 327. Indeed the whole affirmative case that the Board makes for the right to control doctrine is found in a single simplistic paragraph of its Koch opinion:
By the contract under which [the subcontractor] Phillips was to perform its work at the G.E. site or not perform any work at all, Phillips was contractually required to utilize in its work certain prefabricated pipe which had not been worked on by the employees the [union] Respondents represented. Thus, although the Respondent’s claim of work preservation was indeed valid, Phillips by its contract with [the general contractor] Koch had no power to give the Respondents the work they sought, since such work was never Phillips’ to award in the first place. And as Phillips had no past, present, or future authority to award this work to the Respondents, their actions here must have been undertaken in order to produce their effects elsewhere. Therefore, since the pressure directed at Phillips was undertaken for its effect elsewhere, such activity was secondary even though Phillips was the immediate employer here. As the Supreme Court itself said in National Woodwork, “In effect Congress in enacting § 8(b)(4)(A) of the Act (hence this holds for the present Section 8(b)(4)(B)) . . . barred as a secondary boycott union activity directed against a neutral employer, including the immediate employer when in fact the activity directed against him was carried on for its effect elsewhere.”
201 NLRB at 62 (emphasis added; footnotes omitted).
As our opinion elaborates, we remain bewildered as to how Hudik-Ross may be characterized as “neutral” when it executed its contract with Austin in violation of a concededly valid work preservation clause. Nor can we understand how the union’s refusal to acquiesce in that violation must indicate that its objectives were “directed elsewhere,” particularly since Hudik-Ross could itself satisfy the union’s demands, whether by negotiating a compromise with the union or, as in National Woodwork, terminating its tainted contract with Austin.
. Hudik-Ross was free to engage the union in negotiations either before or after it had accepted the subcontracting work. Such negotiations could have centered on an appropriate compromise payment that employees would receive for installing the prefabricated units, although other bargaining solutions were possible. For example, when the collective bargaining agreement was originally accepted the union may have given up demands for additional vacation time or other fringe benefits in order to receive the work preservation guarantee; Hudik-Ross could have achieved a settlement with the union by making concessions on such matters as a quid pro quo for the union’s relaxation of the strictures of Rule IX. Alternatively, Hudik-Ross could have sought an arbitrated solution of the controversy. We cannot understand how, in the absence of such initiatives, Hudik-Ross may be labeled an innocent bystander. The Board appears to place the burden of finding such peaceful resolutions on the union, but we believe that Hudik-Ross, which was the culpable party in generating the controversy, had an obligation to reconcile its actions with its contractual commitments. If Hudik-Ross desires protection from work preservation pressures in the future, it need only negotiate an agreement that incorporates a no-strike provision and that stipulates that such disputes will be submitted to arbitration. Cf. Boys Markets, Inc. v. Retail Clerks Local 770, 398 U.S. 235, 90 S.Ct. 1583, 26 L.Ed.2d 199 (1970). However, no such provision precluded the work stoppage in this case, see note 23 supra, and it is improper for the Board to limit the union’s arsenal of weapons as a matter of law. Cf. NLRB v. Insurance Agents’ International Union, 361 U.S. 477, 497-98, 80 S.Ct. 419, 4 L.Ed.2d 454 (1960). And although the dissent might believe it is “preferable” to resort to such peaceful mechanisms for resolving work preservation controversies, see dissenting op. at n.66, there is no justification in the Act for asserting that arbitration must be employed or that only a suit for contract breach is proper in the circumstances of the case sub judice, see note 38 infra', if the employer seeks to exclude certain instruments from the union’s armamentarium, the collective bargaining process accords him an adequate and appropriate mechanism for doing so.
What would appear to be a paradigmatic voluntary vehicle for peacefully settling work preservation disputes, both allowing the subcontractor to bid for construction contracts involving prefabricated products and guaranteeing union compensation for an employer’s breach of his collective bargaining agreement, was executed by several of the parties involved in Associated General Contractors of California, Inc. v. NLRB, supra note 3. There a trade council composed of 17 local unions and a trade association of employers .in the construction industry had negotiated a work preservation agreement; if a union representative believed that the agreement was being violated, the union could require the employer to cease doing the contested work, but only for a period of 72 hours, while a joint arbitration board investigated the merits of the claim. After the expiration of 72 hours, the employer could resume work whether or not the investigation was complete. The arbitration board could make a variety of appropriate awards against an offending employer, including “payjment of] the equivalent in wages and fringe- benefits lost by employees * * * ” into the union’s pension fund. Nevertheless, the court in that case found the arbitration board’s assessment against the offending employer of approximately $560 to be improper since it determined that, to the extent the agreement covered work not within a subcontractor’s legal control, it was a prohibited “hot cargo” clause in violation of § 8(e), and that enforcement of that clause constituted a violation of § 8(b)(4)(B).
. There was no evidence that the union would have installed the Slant/Fin units if the employees who worked on the internal piping off the jobsite had been organized in an affiliated labor organization. Nor was there any evidence that the union’s actions were motivated by, or that the union was familiar with, the organizational status of the Slant/Fin employees. Cf. National Woodwork, 386 U.S. at 646, 87 S.Ct. at 1269.
. Congress was concerned with the injury suffered by neutral employers, but only where the injury resulted from the use of a secondary boycott. Almost every strike causes economic loss to one or more employers who are unconcerned with the labor dispute. A coal distributor may go bankrupt because of a coal strike. A small steel fabricator may be forced to close his doors because of a major steel strike. Such economic losses as these far outweigh the losses caused by secondary boycotts. Yet Congress has not sought to aid these neutrals * * * -phis point is significant — and sometimes overlooked — because it shows that, while harm to a neutral is an essential ingredient of a secondary boycott, such injury is not by itself objectionable in the eyes of the legislature.
Tower, A Perspective on Secondary Boycotts, 2 Lab.L.J. 727, 732 (1951), quoted with approval in Lesnick, The Gravamen of the Secondary Boycott, 62 Colum.L.Rev. 1363, 1411-12 (1962). See also Note, supra note 3, 77 Yale L.J. at 1416-17. The dissent, however, apparently fails to distinguish between the impermissible objectives of secondary activity and the permissible effects of primary activity. See, e. g., dissenting op., 172 U.S.App.D.C. at 270, 521 F.2d at 930 (manufacturer may be “materially affected”); id. 172 U.S.App.D.C. at 277, 521 F.2d at 937 (referring to “secondary effects of impermissible magnitude”); id. 172 U.S.App.D.C. at 280, 521 F.2d at 940 (“prohibited secondary effects and objects”); id. at nn.78 & 87. See also Local 636, supra note 16, 139 U.S.App.D.C. at 168-69, 430 F.2d at 909-10.
Our conclusion as to the legality of the union’s activity might be different if the union actively sought termination of the Slant/Fin contract by exerting pressure directly against Austin. Cf. National Woodwork, 386 U.S. at 630-31, 87 S.Ct. 1250. In such circumstances, termination of that contract would not simply be an ancillary effect of the union’s primary action, but an objective whose legality would have to be assessed independently. If HudikRoss is recognized as the primary employer for purposes of this work preservation dispute, the Board might reconsider whether Austin might appropriately be held to be a neutral party against whom economic pressure could not be directly applied. See note 44 infra. We note, however, that contrary to the assertions of the dissenting judges, see, e. g., dissenting op., 172 U.S.App.D.C. at 256, 258, 270, 521 F.2d at 916, 918, 930, the mere fact that on a single occasion the union “informed Austin * * * that it would not let Hudik install the climate control units involved,” JA at 254, does not constitute sufficient evidence to indicate that impermissible pressure was directed against Austin. Indeed, in simply informing the general contractor, contemporaneously with the arrival of the prepiped units on the jobsite and the initial notification of Hudik concerning the union’s belief that the work was guaranteed to it by Rule IX, that the union would not install those units “because the piping inside the units was steamfitters’ work,” id. at 235, the union was doing no more than Hudik-Ross should have done in apprising Austin of the fact that Hudik-Ross’ conflicting contractual commitments had generated a labor controversy at the jobsite. However, we nevertheless leave the question of whether there are additional indicia that the union’s pressures were actually directed against Austin (and that Austin was a neutral in the dispute) open for the Board’s consideration on remand.
. 386 U.S. at 627, 87 S.Ct. at 1259. The Board contends that these possible effects cannot be deemed ancillary because “it is impossible to achieve [them] except by the forbidden means of forcing another independent contract tor to change its policy or terminate a business relation.” Brief for the NLRB at 26. However, as we stressed in our discussion of Hudik-Ross’ neutrality, it was possible for HudikRoss to effectively satisfy the union’s demands without affecting the contractual rights of any third party. Moreover, the mere fact that meeting a union’s demands requires termination of contracts with third parties does not invariably indicate the presence of secondary activity. See National Woodwork; 172 U.S. App.D.C. pp. 242-243, 521 F.2d 902-903, infra. The dissent, like the Board, apparently also fails to comprehend that work preservation clauses are essentially fashioned to preserve employees’ wages, and that negotiated settlements, within a subcontractor’s power to achieve, may be arrived at in order to compensate the employees for the subcontractor’s breach of his collective bargaining agreement. See, e. g., dissenting op., 172 U.S.App.D.C. at 256-257, 521 F.2d at 916-917 (presuming disputed work would actually have to be redone rather than resolved through a monetary settlement); id. 172 U.S.App.D.C. at 258, 521 F.2d at 918 (only Austin could comply with union’s demands); id. 172 U.S.App.D.C. at 260, 521 F.2d at 920 (“absurdity” to believe union pressure directed against Hudik, which could not meet demands); id. at 264, 521 F.2d at 924 (demands could only be met by dismantling manufactured articles at jobsite and redoing work); id. 172 U.S.App.D.C. at 271, 521 F.2d at 931 (“Hudik’s alternatives were either to bid on the Norwegian Home contract in spite of the contractual conflict or to have insufficient work for its employees”), id. 172 U.S.App.D.C. at 272-273, 521 F.2d at 932-933 (dispute cannot logically be with subcontractor, who cannot meet demands); id. 172 U.S. App.D.C. at 274, 281, 521 F.2d at 934, 941 & nn.66 & 74.
. The Board, apparently cognizant of the inequities produced by its right to control doctrine in a case such as the present one, indicates that “the doctrine does not foreclose a union from enforcing a work preservation provision against an employer who lacks control of the work through a lawsuit or contractual arbitration procedures.” Brief for the NLRB at 5 n.4, citing Koch. See also dissenting op., 172 U.S.App.D.C. at 278-281, 521 F.2d at 938-941 & nn.66, 95, 101, 106. Koch, in suggesting that the union’s “remedy may well lie in a civil suit for breach of contract,” see 201 NLRB at 63, cited Local 1976, Carpenters v. NLRB [Sand Door], 357 U.S. 93, 108, 78 S.Ct. 1011, 2 L.Ed.2d 1186 (1958), as support for that position. (Nor does the dissent cice any additional support.) It is sufficient to observe that the suggestion — that an agreement to preserve work from nonjobsite prefabrication is legal and enforceable in court even though it obligates the employer to do that which the union could not exert economic pressure to force the employer to do — is completely untenable in light of the congressional overruling of Sand Door by the passage of § 8(e) and the National Woodwork Court’s formulation of the in pari materia relationship of §§ 8(e) and 8(b)(4)(B). See 386 U.S. at 644-45, 87 S.Ct. at 1268 (majority opinion); id. at 649, 87 S.Ct. at 1271 (memorandum of Mr. Justice Harlan) (“§ 8(e), it is agreed, is to be taken pari passu” with § 8(b)(4)(B)); id. at 660, 87 S.Ct. at 1276, quoting Ohio Valley Carpenters, 136 NLRB 977, 987 (1964) (Stewart, J., dissenting) (“there is little point and no logic in declaring an agreement lawful under 8(e), but in finding its enforcement condemned under 8(b)(4)(B)”).
It is thus inescapable that approval of the Board’s right to control test necessarily would preclude a successful union suit for breach of a work preservation agreement whenever the employer who breached the agreement did not have legal control over the work the union desired preserved. See, e. g., Associated General Contractors of California, Inc. v. NLRB, supra note 3. For employees dealing with employers regularly in such a position, collective bargaining and other concerted efforts to protect their traditional work and income from “onrushing technological change,” see Nation*242al Woodwork, 386 U.S. at 640, 87 S.Ct. at 1266, would be substantially undermined. Though we do not necessarily believe that the tug and pull of collective bargaining and concerted economic activity provide the ideal means to accommodate the job and income security of American laborers with the efficiencies of automation, we no more than the National Woodwork Court can say that Congress, without debate and study, intended by its enactment of §§ 8(e) and 8(b)(4)(B) to block this traditional and legislatively protected approach to such a serious industrial relations problem. See generally, 386 U.S. at 640-44, 87 S.Ct. 1266-70. And although the dissenters insist that our decision “increases the costs of construction projects suited to preprepared components,” dissenting op., 172 U.S.App.D.C. at 281, 521 F.2d at 941, the National Woodwork Court has instructed us that such “economic and technological factors * * * are addressed to the wrong branch of government. * * * [Such arguments should be left] for Congress.” 386 U.S. at 644, 87 S.Ct. at 1269.
. The dissenters in National Woodwork felt that Denver supported the prohibition of ail work preservation clauses. See 386 U.S. at 651, 87 S.Ct. at 1271. Clearly the majority rejected this argument.
. National Woodwork, 386 U.S. at 644, 87 S.Ct. at 1268.
. Id. at 645, 87 S.Ct. at 1268.
. We also note that both here and in National Woodwork the union was applying economic pressure to enforce a valid contractual provision between its members and their employer. In Denver action was not taken pursuant to any lawful bargaining agreement.
. “Strongly held opposing views have invariably marked controversy over labor’s use of the boycott to further its aims by involving an employer in disputes not his own. But congressional action to deal with such conduct has stopped short of proscribing identical activity having the object of pressuring the employer for agreements regulating relations between him and his own employees.” National Woodwork, 386 U.S. at 620, 87 S.Ct. at 1255.
.The Board maintains that this circuit and those other courts which have rejected the right to control doctrine have improperly converted the search for proscribed union activity from an analysis of whether an object of the union is secondary to an analysis of whether the principal object of the union is secondary. See brief for the NLRB at 27-28. The Board thus criticizes these courts because they “seem to conclude that if the union is seeking to enforce a valid work preservation clause *244against the employer who signed it, then in every instance, without further inquiry, such activity is primary because motivated by a work preservation objective and enforced against the immediate employer.” Local 438, Plumbers & Pipe Fitters, supra note 4, 201 NLRB at 62 (footnote omitted; emphasis added). See also, e. g., dissenting op. 172 U.S. App.D.C. at 274-275, 521 F.2d at 934-935 & nn.87 & 102. We must respectfully inform the Board that it has totally misunderstood the import of our prior decisions and, we presume, those of our sister circuits. Admittedly, the Board’s statement is correct to the extent that under those circumstances we presume, absent evidence to the contrary, that the union’s activity is primary and lawful and that the employer’s mere lack of legal control over the work does not overcome that presumption. It is also true that, when the pressure is exerted solely against the immediate employer, we would consider termination of the subcontract or the general contractor’s contract with the manufacturer to be acceptable ancillary effects of the primary action. However, even when we find that the union’s primary motivation is work preservation, we will hold its actions unlawful under § 8(b)(4)(B) if they are tainted by secondary objectives. Several examples can illustrate the differences of such situations from the present case.
, The first situation would be one in which the union, in furtherance of a work preservation agreement with a subcontractor, not only refuses to handle prefabricated goods, but also exerts pressure directly against the general contractor to terminate its contract with the manufacturer. Cf. NLRB v. Local 825, Operating Eng’rs [Burns and Roe], 400 U.S. 297, 91 S.Ct. 402, 27 L.Ed.2d 398 (1971). In such cases, it would be appropriate to consider the general contractor to be a neutral party since he should not be forced to investigate the collective bargaining agreements of each of his subcontractors and since he could presume that they would resolve their own disputes with their own employees.
A second situation would be one in which the union discriminates in its work preservation tactics on the basis of the organizational status of the manufacturer. For example, when a dispute arose over work preservation and the disputed work was performed by an affiliated labor organization, the union may have only sought compensatory pay and submitted the dispute to arbitration. Yet in similar circumstances, when the manufacturer’s employees were nonunionized, the union may have struck against its employer, hoping it-would pressure the general contractor to terminate the manufacturer’s contract. Given such facts, the valid work preservation objective could be held to be tainted by the improper secondary objective.
We recognize that such secondary objectives will not often be found when the union’s principal objective is work preservation. We merely wish to demonstrate that we are cognizant of the statutory mandate and that we will hold such secondary objectives to be unlawful should they be detected. However, given the Supreme Court’s approval of work preservation clauses in National Woodwork, and the policy of allowing contending parties to support their demands through economic pressures, we do not find that a work preservation action such as the one in the present case necessarily has per se any unlawful secondary objective, although it may have severe effects on neutral employers.
. 386 U.S. at 644, 87 S.Ct. at 1268.
. For example, such a reconsideration might challenge the Board’s assumption that the union was not in fact attempting to organize the Slant/Fin employees.
. The National Woodwork Court stated that the relevant “circumstances might include the remoteness of the threat of displacement by the banned product or services, the history of labor relations between the union and the employers who would be boycotted, and the economic personality of the industry. See Comment, 62 Mich.L.Rev. 1176, 1185 et seq. (1964).” 386 U.S. at 644 n.38, 87 S.Ct. at 1268. In its analysis of the evidence supporting the Board’s finding that the carpentry union’s ultimate objective was work preservation, the Court stressed that the union “refused to hang prefabricated doors whether or not they bore a union label, and even refused to install prefabricated doors manufactured off the jobsite by members of the Union.” Id. at 646, 87 S.Ct. at 1269. In short, the substance, history, and motivation of the particular dispute must be examined, with particular emphasis on identifying the employer whose labor relations are being affected.