(dissenting as to the claim and concurring as to the counterclaim):
The compulsion felt by my brothers to apply the New York Court of Appeals’ Spivak decision to reach what seems a palpably unjust result reminds me of Chief Justice Erie’s observation as to the occasional predilection of the best of judges for “a strong decision,” to wit, one “opposed to common-sense and to common convenience.” 1 I do not believe a federal court is so hamstrung by New York’s parochialism as my brothers think it to be; one of the very purposes of federal jurisdiction is to protect against state policies that fail to recognize the extent to which the many have become one. Spanos’ services were rendered in the prosecution of a federal claim in the same federal district court where he is seeking to recover the fee his client *168promised him. When that court has chosen to do now what it would assuredly have done if Skouras’ bevy of New York lawyers had seen to it that their California brother had earlier sought admission pro hac vice, I see no reason why we should interfere. And, as my brothers agree, once Spanos has been so admitted, the supremacy clause insulates him from New York decisions drastically limiting the permissible activity of out-of-state attorneys.
I would allow Judge Wyatt’s fair and sensible decision to stand.
Before LUMBARD, Chief Judge, and WATERMAN, MOORE, FRIENDLY, SMITH, KAUFMAN, HAYS, ANDERSON and FEINBERG, Circuit Judges.
On Reconsideration in Banc
FRIENDLY, Circuit Judge.The panel that heard this appeal, consisting of Chief Judge Lumbard, Judge Smith and the writer, found no merit in any of the defendants’ challenges to the judgment below in favor of Spanos except the claim, which the majority sustained over my dissent, that the contract for his legal services violated § 270 of the New York Penal Law, McKinney’s Consol.Laws, c. 40, condemning the unlicensed practice of law, as recently construed in Spivak v. Sachs, 16 N.Y.2d 163, 263 N.Y.S.2d 953, 211 N.E.2d 329 (1965). We later ordered that the appeal be reconsidered in banc; the parties were given leave to file additional briefs and bar associations were permitted to file amici briefs on the defense of illegality.1 The conclusion of the full court differs from that of the panel.
In the first place, we think Judge Wyatt was correct in concluding that a right to recover could be predicated on Rule 3(c) of the District Court for the Southern District of New York providing that “[a] member in good standing of the bar of any state * * * may upon motion be permitted to argue or try a particular cause in whole or in part as counsel or advocate.” The contract engaging Spanos to work on the suit for damages under the antitrust laws, 15 U.S.C. § 15, which defendants proposed to bring in the Southern District can fairly be construed as contemplating court appearances on his part. When the defendants engaged him to that end, they impliedly assumed the obligation of having their New York lawyers in the action make any motion that was necessary to render such appearances lawful. There is not the slightest reason to suppose that if by their lawyers defendants had sought admission pro hac vice for the colleague whose services they had been at such pains to secure, the motion would have been denied; Judge Wyatt found that Spanos “is well trained in law and is a member in good standing of the California bar,” that there was no suggestion of any unlawyerlike conduct on his part, and that accordingly it “cannot seriously be doubted that at any time on motion, the admission of Spanos pro hac vice would have been authorized by this Court.” 235 F.Supp. 1, at 11. Compare Schifrin v. Chenille Mfg. Co., 117 F.2d 92 (2 Cir.), cert. denied, 313 U.S. 590, 61 S.Ct. 1114, 85 L.Ed. 1545 (1941) ; Atchi*169son, T. & S. F. Ry. v. Jackson, 235 F.2d 390 (10 Cir. 1956). We cannot accept the contention that if such leave to appear had been sought and granted, Spanos could recover only for court appearances and not for other legal work in the suit; under 28 U.S.C. § 1654, stemming from § 35 of the First Judiciary Act, 1 Stat. 92 (1789), the grant of leave would have given official recognition to his status as an attorney in the district for all purposes of the action and would have insulated him from § 270 of the New York Penal Law with respect to any legal services reasonably incident to the activities the District Court had authorized. Spanos’ contract was thus susceptible of being lawfully performed without his being admitted to the New York bar and cannot be considered an illegal bargain. Such is the holding of Tuppela v. Mathison, 291 F. 728 (9 Cir. 1923), and Cochran v. Burdick, 63 App.D.C. 150, 70 F.2d 754, cert. denied, 293 U.S. 561, 55 S.Ct. 73, 79 L.Ed. 661 (1934). See also In re Waring’s Estate, 47 N.J. 367, 221 A.2d 193 (1966). Cf. 56-70 58th St. Holding Corp. v. Fedders-Quigan Corp., 5 N.Y.2d 557, 186 N.Y.S.2d 583, 159 N.E.2d 150 (1959) ; Cochran v. Hurth, 29 Ohio App. 305, 163 N.E. 560 (1927). Defendants could not render the contract unlawful and unenforceable by discharging Spanos and thereby cutting off his opportunity to validate his status through pro hac vice admission in the industry suit.before a court appearance on his part. “One who unjustly prevents the performance or the happening of a condition of his own promissory duty thereby eliminates it as such a condition. He will not be permitted to take advantage of his own wrong, and to escape from liability for not rendering his promised perfoirmance by preventing the happening of the condition on which it was promised.” 3A Corbin, Contracts § 767, at 540 (1960) ; E. I. DuPont de Nemours Powder Co. v. Schlottman, 218 F. 353 (2 Cir. 1914), cert. denied, 235 U.S. 705, 35 S.Ct. 382, 59 L.Ed. 434 (1915); George W. Garig Transfer, Inc. v. Harris, 226 La. 117, 75 So.2d 28 (1954); Wissahickon Realty Coirp. v. Boyle, 385 Pa. 198, 122 A.2d 720 (1956); 5 Williston, Contracts § 1293A (rev. ed. 1937).
While this would suffice to dispose of the case, the importance of the problem and the desirability of furnishing guidance to the bar lead us to consider other grounds that have been urged for affirmance. The New York County Lawyers’ Association suggests that Spa-nos may have acted under the control and supervision of duly admitted New York attorneys who alone were responsible to the client, in a status resembling that of the unlicensed law clerk which has never been supposed to violate § 270 in the absence of court appearance or a holding out as the giver of independent legal advice. It is clear there was no thought of Spa.nos being the sole lawyer in the industry suit. Defendants’ initial proposal was that he prepare the case for trial by Eugene Sherpick, a prominent New York trial lawyer; Spanos agreed to come to New York only on the understanding that he was to be associated with Dean Landis whom he wanted to be his “link to this case”; and when Mr. Sherpick and Dean Landis formally withdrew in 1956, the agreement between the defendants and Mr. Weisman’s firm for continuing the litigation stated that the firm should “have the aid and cooperation of Nick Spanos.” On the other hand, the record would not support a conclusion that Spanos’ relations with the New York lawyers bore any real analogy to that between a law clerk and his employer. Spanos felt free to criticize the New York lawyers to the client and insisted he “was to have a status in the ease full and equal with that of every other lawyer,” including Mr. Sherpick and Dean Landis; moreover he was generally paid, and ultimately discharged, not by any of the New York lawyers but by the defendants, and claimed an attorney’s lien. We find it unnecessary, however, either to determine precisely what the relationship was or to endeavor to predict whether the New York Court of Appeals would consider Spanos’ conduct within the condem*170nation of § 270 of the Penal Law. For we hold that under the privileges and immunities clause of the Constitution no state can prohibit a citizen with a federal claim or defense from engaging an out-of-state lawyer to collaborate with an in-state lawyer and give legal advice concerning it within the state.
We recognize that the guarantee against abridgment of the privileges and immunities of citizens of the United States could lend itself to “mischievous uses” if its scope were not confined to those interests “growing out of the relationship between the citizen and the national government, created by the Constitution and federal laws,” Adamson v. People of State of California, 332 U.S. 46, 61, 67 S.Ct. 1672, 91 L.Ed. 1903 (1947) (Frankfurter, J., concurring); Colgate v. Harvey, 296 U.S. 404, 444, 56 S.Ct. 252, 266, 80 L.Ed. 299 (1935) (Stone, J., dissenting), overruled, Madden v. Commonwealth of Kentucky, 309 U.S. 83, 60 S.Ct. 406, 84 L.Ed. 590 (1940); and we note the “judicial reluctance to expand the content of national citizenship * * * due to a fear of creating constitutional refuges for a host of rights historically subject to regulation.” Bell v. State of Maryland, 378 U.S. 226, 250, 84 S.Ct. 1814, 1827, 12 L.Ed.2d 822 (1964) (opinion of Douglas, J.). We are persuaded, however, that where a right has been conferred on citizens by federal law, the constitutional guarantee against its abridgment must be read to include what is necessary and appropriate for its assertion. In an age of increased specialization and high mobility of the bar, this must comprehend the right to bring to the assistance of an attorney admitted in the resident state a lawyer licensed by “public act” of any other state who is thought best fitted for the task, and to allow him to serve in whatever manner is most effective, subject only to valid rules of courts as to practice before them. Cf. Lefton v. City of Hattiesburg, 333 F.2d 280, 285 (5 Cir. 1964). Indeed, in instances where the federal claim or defense is unpopular, advice and assistance by an out-of-state lawyer may be the only means available" for vindication. The broadening of district court rules as to admission suggested in the dissenting opinion is no adequate solution. The federal matter on which the help of a non-resident specialist is sought may be pending in a different state or may not be a suit at all, and specialized legal advice may be needed without the delay or expense incident to admission by a federal court before which the attorney may not have any intention of practicing, even if that were available and would afford sufficient validation. Having exercised their constitutional right to obtain the expert legal assistance on their antitrust claim which they desired, defendants cannot be heard to object to paying the bill.
Here, beginning with a paper written while still in law school, Spanos had concentrated on antitrust problems in the motion picture industry — a subject requiring detailed knowledge both of the decisions and of complex business practices ; it was the knowledge and skill thus acquired that the defendants wished to bring to the aid of their New York attorneys in preparing the antitrust suit. Under the Constitution we perceive no basis on which New York could throw up a significant block to such assistance, for example, by making it a crime to engage in more than a one or two day consultation within its borders and insisting that examination of defendants’ files, interviewing of witnesses and other time-consuming tasks essential to the rendition of proper legal advice and the effective pursuit of the antitrust claims should either be left to New York lawyers or be performed at great inconvenience where New York’s writ does not run. The problem is by no means limited to antitrust litigation; similar requirements for specialized legal services frequently arise as to federal rights relating to such esoteric subjects as income taxation, patents, copyrights, trademarks, and securities and labor regulation. If a corporation operating across state lines wishes a particular lawyer or firm of lawyers to supervise the handling of all its prob*171lems in one of such fields, we do not see how a state can constitutionally insist that a local manager come to the expert, bearing bales of papers with him, rather than vice versa. Although in Sperry v. Florida, 373 U.S. 379, 83 S.Ct. 1322, 10 L.Ed.2d 428 (1963), the Court was not required to go so far, our decision accords with the decision’s major thrust —that Florida could not require its inventors desiring the help of patent specialists to betake themselves and their materials to the District of Columbia.2 See also Brotherhood of Railroad Trainmen v. Virginia ex rel. Virginia State Bar, 377 U.S. 1, 7, 84 S.Ct. 1113, 12 L.Ed.2d 89 (1964).
The Association of the Bar of the City of New York urges us to take an even broader ground that would render the participation of a licensed in-state lawyer irrelevant. A good deal can be said for such a position; for example, in the case just put of the corporation having nationwide operations, it would seem absurd that when the out-of-state trademark specialist goes to a local branch, he should be required to obtain the assistance of a resident general practitioner for whose views he would have little regard. Yet there is also a case for the other side. The disparity in requirements for admission to the bar gives a state maintaining high qualification standards some interest in seeing that its residents do not take action even on a federal right solely on the advice of a lawyer from another state; moreover, what is basically a federal claim or defense may depend in part on an “issue or claim which has its source in state law.” Maternally Yours, Inc. v. Your Maternity Shop, Inc., 234 F.2d 538, 541 n. 1 (2 Cir. 1956). We thus limit our holding to the situation here presented, where a citizen has invited a duly licensed out-of-state lawyer to work in association with a local lawyer on a federal claim or defense. Whether § 270 of the New York Penal Law could apply if the client in such a case dispensed with the local attorney or if the matter were one in which federal jurisdiction rested only on diverse citizenship, are questions better left to another day. And we in no way sanction a practice whereby a lawyer not admitted to practice by a state maintains an office there and holds himself out to give advice to all comers on federal matters.
The judgment of the District Court in favor of Spanos is affirmed.
. He continued that “as one strong decision is a precedent for another a little stronger, the law at last, on some matters, becomes such a nuisance that equity intervenes, or an Act of Parliament must be passed to sweep the whole away.” Senior, Conversations with Distinguished Persons 314 (1880 ed.), quoted in Pound, Mechanical Jurisprudence, reprinted in Landmarks of Law 101, 103-04 (1960).
. The positions of the bar associations differ. The Association of the Bar of the City of New York urges affirmance on the broad ground that an attorney licensed in one state may not constitutionally be forbidden to advise with respect to a federal claim in another. The Federal Bar Association of New York, New Jersey and Connecticut advocates affirmance on the grounds that Spanos was acting under the supervision of licensed New York attorneys and that defendants are estopped to question the regularity and propriety of his position. The New York County Lawyers’ Association opposes the idea that an attorney licensed by another state may lawfully give independent advice as to federal matters in New York without having regularized his position through admission pro hac vice or otherwise, but suggests that the record may support a finding that Spanos was at all times working under the direction, control and supervision of one or more members of the New York bar and, if so, there would be no illegality. The New York State Bar Association supports the decision of the panel majority.
. We read the Chief Justice’s qualifying statement that “in the absence of federal legislation, it [Florida] could validly prohibit nonlatoyers from engaging in this circumscribed form of patent practice,” 373 U.S. at 383, 83 S.Ct. at 1325 (emphasis added), to mean exactly what it says.