dissenting.
My disagreement with the Court in this case is a relatively narrow one. I do not disagree with much that is said concerning the history and policies underlying 28 U. S. C. § 2283. Nor do I dispute the Court’s holding on the basis of Amalgamated Clothing Workers v. Richman Bros., 348 U. S. 511 (1955), that federal courts do not have authority to enjoin state proceedings merely because it is asserted that the state court is improperly asserting jurisdiction in an area pre-empted by federal *298law or federal procedures. Nevertheless, in my view the District Court had discretion to enjoin the state proceedings in the present case because it acted pursuant to an explicit exception to the prohibition of § 2283, that is, “to protect or effectuate [the District Court’s] judgments.”
The pertinent portions of the District Court’s 1967 order, denying ACL’s application for injunctive relief and defining BLE’s federally protected right to picket at the Moncrief Yard, are as follows:
“3. The parties to the BLE-FEC 'major dispute,’ having exhausted the procedures of the Railway Labor Act, 45 U. S. C. § 151, et seq., are now free to engage in self-help. Brotherhood of Locomotive Engineers v. Baltimore & O. B. R., 372 U. S. 284 (1963).
“4. The conduct of the FEC pickets and that of the responding ACL employees are a part of the FEC-BLE major dispute. Brotherhood of Locomotive Firemen and Enginemen v. Florida East Coast Ry., 346 F. 2d 673 (5th Cir. 1965).
“6. The 'economic self-interest’ of the picketing union in putting a stop to the interchange services daily performed within the premises of plaintiff’s yard facilities, and in the normal, day-to-day operation of FEC trains operating with strike replacement crews within these facilities is present here. The ‘economic self-interest’ of the responding employees in refusing to handle this interchange and in making common cause with the striking FEC engineers is similarly present. Brotherhood of R. R. Trainmen v. Atlantic Coast Line R. R., 362 F. 2d 649 (5th Cir.), aff’d, 385 U. S. 20 (1966).
“7. The Norris-LaGuardia Act, 29 U. S. C. § 101, and the Clayton Act, 29 U. S. C. § 52, are appli*299cable to the conduct of the defendants here involved. See Brotherhood of Locomotive Firemen and Enginemen v. Florida East Coast Ry., 346 F. 2d 673 (5th Cir. 1965); Brotherhood of R. R. Trainmen v. Atlantic Coast Line Railroad, 362 F. 2d 649 (5th Cir.), aff’d, 385 U.. S. 20 (1966).” App. 67-68.
The thrust of the District Judge’s order is that the procedures prescribed by the Railway Labor Act had been exhausted in relation to the BLE-FEC dispute, that BLE was therefore free to engage in self-help tactics, and that it was properly exercising this federal right when it engaged in the picketing that ACL sought to enjoin. This interpretation of the order is supported by the fact that the District Judge relied upon Brotherhood of Locomotive Engineers v. Baltimore & Ohio R. Co., 372 U. S. 284 (1963), in which this Court held that the parties had exhausted all available procedures under the Railway Labor Act and thus were free to resort to self-help. Furthermore, the District Court invoked § 20 of the Clayton Act, 29 U. S. C. § 52, which provides that certain union activities, including striking and peaceful picketing, shall not “be considered or held to be violations of any law of the United States.” Thus, contrary to petitioner’s contention, the District Court obviously decided considerably more than the threshold question of whether the Norris-LaGuardia Act withdrew jurisdiction to grant federal injunctive relief in the circumstances of this case.
In my view, what the District Court decided in 1967 was that BLE had a federally protected right to picket at the Moncrief Yard and, by necessary implication, that this right could not be subverted by resort to state proceedings. I find it difficult indeed to ascribe to the District Judge the views that the Court now says he held, namely, that ACL, merely by marching across the street to the state court, could render wholly nugatory the *300District Judge's declaration that BLE had a federally protected right to strike at the Moncrief Yard.
Moreover, it is readily apparent from the District Court's 1969 order enjoining the state proceedings that the District Judge viewed his 1967 order as delineating the rights of the respective parties, and, more particularly, as establishing BLE’s right to conduct the picketing in question under paramount federal law. This interpretation should be accepted as controlling, for certainly the District Judge is in the best position to render an authoritative interpretation of his own order. In the 1969 injunction order, after distinguishing Richman Bros, and concluding that the District Court could grant injunctive relief “in aid of its jurisdiction,'' the court alternatively held that it had power to stay the state court proceedings so as to effectuate its 1967 order:
“In its Order of April 26, 1967, this Court found that Plaintiff's Moncrief Yard, the area in question, ‘is an integral and necessary part of [Florida East Coast Railway Company’s] operations.’. . . The Court concluded furthermore that Defendants herein ‘are now free to engage in self-help.’. . . The injunction of the state court, if allowed to continue in force, would effectively nullify this Court’s findings and delineation of rights of the parties. The categorization of Defendants' activities as ‘secondary’ does not alter this state of affairs. See Brotherhood of R. R. Trainmen v. Jacksonville Terminal Co., - U. S. -, 22 L. Ed. 2d 344 (1969). The prohibition of 28 U. S. C. §2283, therefore, does not deprive this Court of jurisdiction to enter the injunction in this instance. Capital Service, Inc. v. NLRB, 347 U. S. 501 (1954); [United Indus. Workers of the Seafarers Int’l Union] v. Board of Trustees of Galveston Wharves, 400 F. 2d 320 (5th Cir. 1968).” App. 195-196.
*301The District Judge’s reliance upon Capital Service, Inc. v. NLRB, 347 U. S. 501 (1954),1 and United Indus. Workers of the Seafarers Int’l Union v. Board of Trustees of Galveston Wharves, 400 F., 2d 320 (C. A. 5th Cir. 1968), a fact ignored by the Court, is particularly significant, for both of these cases sustained in-junctive relief against state court proceedings that threatened to impair the ability of the federal courts to make their judgments effective. Moreover, no matter how the arguments of counsel before the District Court are understood, it is apparent that the District Judge did not bottom the 1969 injunction upon our intervening decision in Jacksonville Terminal but merely cited that case to support the court’s 1967 conclusion that the picketing in question constituted federally protected activity whether or not it had “secondary” aspects.
The Court seeks to bolster its own reading of the District Court’s 1967 and 1969 orders by finding them “somewhat ambiguous” and then by referring to the arguments of counsel before that court and the state court both in 1967 and 1969. In the first place, it should be noted that the argument of counsel is not always a sure guide to the interpretation of a subsequent judicial decree or opinion, because it not infrequently happens, in this Court as well as others, that a decision is based on premises not elaborated by counsel. Indeed, occasionally a decision is grounded on a theory not even suggested by counsel’s argument.
*302In any event, I believe that the Court has misinterpreted the argument of counsel in the lower courts. While I do not find the various proceedings below entirely free of confusion with respect to BLE’s legal theory, there appear to be at least two strands to its argument. To be sure, BLE did contend, particularly in the state proceedings, that our decision in Jacksonville Terminal was controlling on the merits.2 As I read the record, however, BLE also argued that the state injunction should either be dissolved or enjoined so that it would not interfere with the federal court’s 1967 decree. Thus, in moving for a preliminary injunction against the state court proceedings, BLE relied both upon Jacksonville Terminal and upon the power of the District Court to issue the injunction “to protect and effectuate the judgment of this Court dated April 26, 1967.” 1 Record 30-31.
Furthermore, both in support of the motion for a preliminary injunction and during oral argument in the District Court, BLE relied extensively upon Capital Service, Inc. v. NLRB, supra, and United Indus. Workers of the Seafarers Int’l Union v. Board of Trustees of Galveston Wharves, supra. See 1 Record 33-34, 243-245, 247, 253-257, 279-281. A consideration of the factual context of the latter case is instructive in understanding BLE’s position below. In Galveston Wharves *303the union fully complied with the pertinent provisions of the Railway Labor Act, but, because the employer had refused to bargain concerning a “major” dispute, the union was free to strike. Meanwhile the employer obtained from a state court an injunction against any picketing on or near its premises. The Federal District Court ordered the parties to bargain and enjoined the employer from giving effect to, or seeking enforcement of, the state court injunction. The Court of Appeals for the Fifth Circuit affirmed the granting of injunctive relief on the ground that this action was within the § 2283 exception relating to the effectuation of federal court judgments. The Court of Appeals held that the union had a right to strike under the Railway Labor Act and that that right could not be frustrated or interfered with by state court injunctions. Similarly, BLE argued below that resort to state equitable proceedings should not be permitted to undermine the District Court’s prior determination that BLE had a right to picket at the Móncrief Yard. As its injunction order indicates, the District Court was persuaded by BLE’s argument. After the federal injunction was issued, in proceedings brought by ACL to stay the effectiveness of the order, BLE adhered to its position that the state injunction, if not enjoined, would nullify the District Court’s 1967 order delineating the rights of the parties. 1 Record 499, 505, 508-509. Again BLE relied upon the intervening decision in Jacksonville Terminal, but it did so primarily in support of the contention that the 1967 order was proper insofar as it prohibited state court interference with the picketing at the Moncrief Yard. 1 Record 509-510. In essence, BLE argued that the 1967 order had correctly anticipated Jacksonville Terminal. See ibid.
In the state courts BLE adopted a position entirely consistent with the foregoing. For example, in opposing *304ACL’s application for a temporary injunction against the picketing, BLE contended that the District Court had previously held that under controlling federal law BLE’s right to picket had been established, that this declaration of rights was res judicata in the state proceedings, and consequently that state proscription of the picketing was improper. 2 Record 104-105.
In sum, to the extent that the argument of counsel is an interpretive guide to what the District Court actually decided in its 1967 and 1969 orders, the Court’s conclusion that the record “conclusively shows that neither the parties themselves nor the District Court construed the 1967 order” to preclude resort to state remedies to prohibit the Moncrief Yard picketing (ante, at 293) is wholly erroneous. And, quite apart from counsel’s argument, it is apparent that the District Judge viewed his own 1967 order as delineating a federally protected right for the BLE picketing in question. Whether the District Court’s anticipation of Jacksonville Terminal was correct in the circumstances of the present case is not now before us. But if the 1967 order is so understood, it is undeniably clear that the subsequent injunction against the state proceedings was both necessary and appropriate to preserve the integrity of the 1967 order.
In justifying its niggardly construction of the District Court’s orders, the Court takes the position that any doubts concerning the propriety of an injunction against state proceedings should be resolved against the granting of injunctive relief. Unquestionably § 2283 manifests a general design on the part of Congress that federal courts not precipitately interfere with the orderly determination of controversies in state proceedings. However, this policy of nonintervention is by no means absolute, as the explicit exceptions in § 2283 .make entirely clear. Thus, § 2283 itself evinces a congressional intent that *305resort to state proceedings not be permitted to undermine a prior judgment of a federal court. But that is exactly what has occurred in the present case. Indeed, the federal determination that BLE may picket at the Moncrief Yard has been rendered wholly ineffective by the state injunction. The crippling restrictions that the Court today places upon the power of the District Court to effectuate and protect its orders are totally inconsistent with both the plain language of § 2283 and the policies underlying that statutory provision.
Accordingly, I would affirm the judgment of the Court of Appeals sustaining the District Court’s grant of in-junctive relief against petitioner’s giving effect to, or availing itself of, the benefit of the state court injunction.
In Capital Service the NLRB sought an injunction against certain picketing under § 10 (1) of the National Labor Relations Act, 29 U. S. C. § 160 (l). Previously a state court had restrained the very conduct that the District Court was asked to enjoin. This Court decided that the District Court had authority to enjoin the state proceedings so that it would have “unfettered power to decide for or against the union, and to write such decree as it deemed necessary in order to effectuate the policies of the Act.” 347 U. S., at 505-506.
It is hardly surprising that BLE emphasized the Jacksonville Terminal decision in the state proceedings to dissolve the state injunction, and this reliance is hardly inconsistent with the position that the federal court in 1967 had authoritatively delineated BLE’s federally protected right to strike at the Moncrief Yard. BLE may well have thought that its contention that Jacksonville Terminal was controlling on the issue of pre-emption would carry more weight with the state court than the alternative position that the protected character of the BLE picketing had been previously determined by the Federal District Court.