with whom Mr. Justice Brennan, Mr. Justice Marshall, and Mr. Justice Stevens join, dissenting.
The Court holds today that a labor union locked in a direct economic confrontation with an employer is powerless to impose sanctions on its own members who choose to pledge their loyalty to the adversary. Nothing in §8 (b)(1)(B) or any other provision of the National Labor Relations Act permits such a radical alteration of the natural balance of *439power between labor and management. I therefore respectfully dissent.
A union’s ability to maintain a unified front in its confrontations with management and to impose disciplinary sanctions on those who “adher[e] to the enemy in time of struggle” are essential to its survival as an effective organization. See Summers, Legal Limitations on Union Discipline, 64 Harv. L. Rev. 1049, 1066 (1951). An employer also has an interest in securing the loyalty of those who represent him in dealings with the union, and that interest is protected by specific provisions of the Act.1 Thus, as the Court observed in Florida Power & Light Co. v. Electrical Workers, 417 U. S. 790 (FP&L), very real concerns are raised on both sides when supervisory employees with collective-bargaining and grievance-adjustment responsibilities are also union members. But §8(b)(l)(B) is not “any part of the solution to the generalized problem of supervisor-member conflict of loyalties.” 417 U. S., at 813.
That statutory provision was enacted for the primary purpose of prohibiting a union from exerting direct pressure on an employer to force him into a multiemployer bargaining unit or to dictate his choice of representatives for the settlement of employee grievances. S. Rep. No. 105, 80th Cong., 1st Sess., pt. 1, p. 21 (1947). The Court in FP&L reserved decision on whether union pressure expressly aimed at affecting the manner in which supervisor-members performed their collective-bargaining or grievance-adjustment functions might *440fall within the “outer limits” of the proscription of § 8 (b) (1)(B). 417 U. S., at 805. See San Francisco-Oakland Mailers’ Union No. 18 (Northwest Publications, Inc.), 172 N. L. R. B. 2173. But it flatly rejected the argument that union discipline aimed at enforcing uniform rules violated §8 (b)(1)(B) simply because it might have the ancillary effect of “depriv[ing] the employer of the full allegiance of, and control over, a representative he has selected for grievance adjustment or collective bargaining purposes.” 417 U. S., at 807.
In the present cases it is entirely clear that the union had no interest in restraining or coercing the employers in the selection of their bargaining or grievance-adjustment representatives, or in affecting the manner in which supervisory employees performed those functions. As the Court notes, ante, at 417-418, and n. 6, the union expressed no interest at the disciplinary trials in the kind of work that was done behind its picket lines. Its sole purpose was to enforce the traditional kinds of rules that every union relies on to maintain its organization and solidarity in the face of the potential hardship of a strike. Cf. NLRB v. Allis-Chalmers Mfg. Co., 388 U. S. 175, 181-184.
In reversing the judgment of the Court of Appeals, this Court today forbids a union from disciplining a supervisor-member who crosses its picket line — who clearly gives “aid and comfort to the enemy” during a strike, see Summers, supra, at 1066 — solely because that action may have the incidental effect of depriving the employer of the hypothetical grievance-adjustment services of that particular supervisor for the duration of the strike. This ruling quite simply gives the employer the superior right .to call on the loyalty of any supervisor with grievance-adjustment responsibilities,2 when*441ever the union to which the supervisor belongs calls him out on strike. In short, the Court’s decision prevents a union with supervisory members from effectively calling and enforcing a strike.3
Nothing in §8 (b)(1)(B) permits such a sweeping limitation on the choice of economic weapons by unions that include supervisory employees among their members. On the contrary, as the Court clearly held in FP&L, supra, an employer’s remedy if he does not want to share the loyalty of his supervisors with a union is to insist that his supervisory personnel not belong to a union; or if he does not welcome the consequences of his supervisors’ union membership he may legally penalize them for engaging in union activities, see n. 1, supra, or “resolv[e] such conflicts as arise through the traditional procedures of collective bargaining.” FP&L, supra, at 813.4
The sole function of §8 (b)(1)(B) is to protect an employer from any union coercion of the free choice of his bargaining or grievance-adjustment representative. In prohibiting union interference in his choice of representatives for dealings with the union, this statutory provision does not in any *442way grant him a right to interfere in the union’s relationship with its supervisor-members.5 The statute leaves the balance of power in equipoise. The Court’s decision, by contrast, tips it measurably in favor of the employer at the most delicate point of direct confrontation, by completely preventing the union from enlisting the aid of its supervisor-members in a strike effort. It seems to me that the Court’s reading of § 8 (b)(1)(B) is “fundamentally inconsistent with the structure of the Act and the function of the sections relied upon.” American Ship Building Co. v. NLRB, 380 U. S. 300, 318.
Accordingly, I would affirm the judgment of the Court of Appeals.
This interest is protected by § 2 (3) of the National Labor Relations Act, which excludes “supervisors” as defined in §2 (11) from the definition of “employees,” thereby excluding them from the coverage of the Act. Thus an employer may discharge or otherwise penalize a supervisory employee for engaging in what would otherwise be protected concerted activity under the Act. In addition, § 14 (a) of the Act provides that “no employer . . . shall be compelled to deem . . . supervisors as employees for the purpose of any law . . . relating to collective bargaining.” See Florida Power & Light Co. v. Electrical Workers, 417 U. S. 790, 808-811.
Since the power to adjust employee grievances is one of the statutory indicia of supervisory status under §2 (11) of the Act, many if not most *441supervisory employees will fall within the Court’s ruling when they are “restrainfed] . . . from going to work and from performing the normal duties of their positions, which includ[e] the adjustment of grievances.” Ante, at 431-432.
Under this rule, it would appear that a separate union consisting entirely of supervisory employees would commit an unfair labor practice if it ordered its members not to cross the picket lines of another union, or indeed, if it called an economic strike entirely on its own, since the employer would thereby be deprived of the services of his chosen grievance-adjustment representatives.
Alternatively, the employer may ease the dilemma of his supervisory employees by offering to provide their defense or to indemnify them against any fines that might be imposed by the union for a breach of strike discipline. Several of the employers in this case did in fact extend such offers to the hyphenates. See decision of the Administrative Law Judge, App. to Pet. for Cert, in No. 76-1162, p. 42a.
In San Francisco-0akland Mailers Union No. 18 (Northwest Publications, Inc.), 172 N. L. R. B. 2173, the Board found a violation of § 8 (b) (1) (B) when a union expelled member-foremen for allegedly assigning bargaining-unit work in violation of the collective-bargaining agreement. It reasoned that the employer’s statutory right to choose his bargaining representative would be rendered illusory if the union could effectively control the actions of any individual who happened to occupy the position. I adhere to the view expressed by the Court in FP&L, 417 U. S., at 805, that this ruling is at best within the “outer limits” of § 8 (b)(1)(B).