concurring in part and dissenting in part.
In this action, the plaintiff-employee seeks a judicial remedy against his former employer for wrongful discharge, and against his union for breach of the duty of fair representation. The District Court granted summary judgment in favor of both defendants because of the employee’s failure to file suit within what that court viewed as the appropriate period of limitations. The Court of Appeals reversed the District Court’s judgment as to both claims and remanded for further proceedings. The employer alone sought further review in this Court. Therefore, at this stage of the litigation, the only question properly presented for our consideration is whether the Court of Appeals chose the most appropriate New York statute of limitations to govern the employee’s claim against his former employer for wrongful discharge.1 Although I agree for the most part with the *72Court's resolution of that question, I fear that its failure expressly to limit its reasoning to the narrow question presented in this case may suggest that today’s decision also resolves the question whether the same statute of limitations governs the employee’s claim against the union for breach of the duty of fair representation. That interpretation, although understandable in light of the broad language of the Court’s opinion, would be inconsistent with the procedural posture of this case and, in addition, would be conceptually unsound.
I concur in the Court’s conclusion that it is appropriate, for purposes of federal labor law, to characterize the employee’s suit against his employer as an action to set aside an arbitration award. In the arbitration proceeding that took place prior to this litigation, the employer prevailed on the precise claim respondent raises against it in this judicial proceeding — that the discharge violated the collective-bargaining agreement. If the employee now were to prevail against the employer on this claim, the necessary effect of the resulting court order would be to undo the arbitration award. See ante, at 61. Accordingly, in upholding the employer’s position, the Court properly emphasizes the importance of the finality and certainty of arbitration in the collective-bargaining context, and properly treats the adverse arbitration decision as a substantial obstacle to the employee’s pursuit of judicial relief against his employer.
The employee’s claim against his union for breach of the duty of fair representation, however, is of a far different character. Although this claim is closely related to the claim *73against the employer, the two claims are nonetheless conceptually distinct.2 The claim against the union may not, in my judgment, be characterized as an action to vacate an arbitration award. The arbitration proceeding did not, and indeed, could not,3 resolve the employee's claim against the union. Although the union was a party to the arbitration, it acted only as the employee’s representative; the Joint Panel did not address or resolve any dispute between the employee and the union. Therefore, with respect to the employee’s action against the union, the finality and certainty of arbitration are not threatened by the prospect that the employee might prevail on his judicial claim. Because no arbitrator has decided the primary issue presented by this claim, no arbitration award need be undone, even if the employee ultimately prevails.4
*74The employee’s claim against his union is properly characterized, not as an action to vacate an arbitration award, but rather as a malpractice claim. There is no conceptual reason why that claim may not survive even if the employer is able to rely on the arbitration award as a conclusive determination of its obligations under the collective-bargaining agreement.5 Thus, by analogy, a lawyer who negligently allows the statute of limitations to run on his client’s valid claim may be liable to his client even though the original defendant no longer has any exposure. Cf. Smart v. Ellis Trucking Co., 580 F. 2d 215, 218-219 (CA6 1978), cert. denied, 440 U. S. 958.
In this case, I agree with the Court that the statute of limitations applicable to respondent’s claim against his former employer is the 90-day statute governing actions to vacate or *75modify arbitration awards in New York.6 It surely does not follow, however, that that statute is applicable to the claim against the union for breach of its duty of fair representation.7 Because the union did not seek review of the judgment of the Court of Appeals, it is not appropriate to decide what period of limitations should be applied to the employee’s claim against it. It is, however, noteworthy that Justice Stewart’s proposal that we strain to conclude that Congress intended that § 10 (b) of the National Labor Relations Act, 29 U. S. C. § 160 (b),8 be applied to causes of action that this *76Court had not yet divined when § 10 (b) was enacted,9 cf. Watt v. Alaska, post, p. 276 (Stewart, J., dissenting), rests on a rationale that might apply to a § 301 claim against the union, but which is wholly inapplicable to the claim against the employer, because the employer is not accused of any unfair labor practice.
In sum, I concur in the Court’s judgment insofar as it pertains to the employee’s action against his employer.
The union did not petition for review of the Court of Appeals’ decision, and the employer has not taken a position with respect to which statute of limitations governs the employee’s claim against the union. Indeed, the employer has vigorously denied that this question is presented in this case:
“[T]he only question raised in the petition for certiorari is the statute of *72limitations applicable to Mitchell’s claim against his employer, UPS. See Liotta v. National Forge Co., 629 F. 2d 903 (3d Cir.1980).
“The fact that Mitchell may have a claim against the Union does not affect the determination of which statute of limitations governs his claim against his employer. See Liotta v. National Forge Co., supra, 629 F. 2d at 905.” Reply Brief for Petitioner 3, 4.
See also Id,, at 5-6.
The claims are closely related because, to prevail against the employer, the employee must establish that the union breached its duty of fair representation and that the employer breached the collective-bargaining agreement; similarly, to prevail against the union, the employee must prove that the union breached its duty of fair representation and, if he wishes to recover loss-of-employment damages for which the union is responsible, that the employer breached the agreement. See n. 4, infra. Cf. Czosek v. O’Mara, 397 U. S. 25, 28-29. However, despite this close relationship, the two claims are not inseparable. Indeed, although the employee in this case chose to sue both the employer and the union, he was not required to do so; he was free to institute suit against either one as the sole defendant. See Vaca v. Sipes, 386 U. S. 171, 186-187.
By its very nature, the employee’s claim that the union breached its duty of fair representation cannot be resolved in an arbitration proceeding because it arises out of the conduct of that proceeding itself.
While an arbitration decision favorable to the employer — for example, that the discharge did not breach the collective-bargaining agreement— would be of substantial significance in an employee’s suit against his union, it would not necessarily be dispositive. The determination whether the employer breached the agreement may be highly relevant to the amount of damages caused by the union’s alleged breach of duty, but it is not necessarily controlling with respect to the threshold question whether there was any breach of duty by the union at all. For example, if, solely for reasons of racial bias, a union processes a discharged employee’s griev-*74anee in bad faith, the union breaches its duty of fair representation. Cf. Steele v. Louisville & Nashville R. Co., 323 U. S. 192. The fact that the underlying discharge may not have violated the collective-bargaining agreement does not necessarily absolve the union of liability for its breach, although it may limit the size of the employee’s recovery against the union. Thus, while a court considering an employee’s claim against a union will evaluate the validity of the employer’s underlying conduct, that evaluation is not central to the resolution of the duty-of-fair-representation claim.
In Liotta v. National Forge Co., 629 F. 2d 903 (CA3 1980), cert. pending, No. 80-890, the Court of Appeals concluded that the Pennsylvania statute of limitations governing actions to vacate arbitration awards should apply to an employee’s § 301 action against his employer for wrongful discharge. However, in Liotta the employee had filed suit only against his employer, and not against his union. The Court of Appeals suggested that this fact was of some significance in determining which statute of limitations to apply:
“[T]he fact that Liotta alleges that the arbitration award is invalid due to the Union’s breach of its duty of fair representation does not change the limitations period because the suit here is against the Company and not the Union. Thus, it is clear that Liotta was dissatisfied with and simply seeks to upset the arbitrator’s decision that the Company did not wrongfully discharge him.” 629 F. 2d, at 905-906.
N. Y. Civ. Prac. Law § 7511 (a) (McKinney 1963), quoted ante, at 59. I do not address any question concerning the possible tolling of that period, because no such issue is presented in this case.
Under the rationale of Auto Workers v. Hoosier Cardinal Corp., 383 U. S. 696, 704-705, arguably the proper statute of limitations to apply to such a claim would be N. Y. Civ. Prac. Law § 214 (6) (McKinney 1972), which governs claims for nonmedical malpractice. Because the question of the appropriate statute of limitations to apply to the employee’s claim against his union is not properly presented in this case, I express no definite opinion on the point. I note, however, that the Court dismisses the suggestion that this action may be characterized as a malpractice action with the observation that this characterization “overlook [s] the fact that an arbitration award stands between the employee and any relief which may be awarded against the company.” Ante, at 63, n. 4 (emphasis supplied). Because no arbitration award stands between the employee and any relief which may be awarded against the union, this observation is inapplicable to the claim against the union.
Section 10 (b) of the National Labor Relations Act provides:
“Whenever it is charged that any person has engaged in or is engaging in any such unfair labor practice, the [National Labor Relations] Board, or any agent or agency designated by the Board for such purposes, shall have power to issue and cause to be served upon such person a complaint stating the charges in that respect, and containing a notice of hearing before the Board or a member thereof, or before a designated agent or agency, at a place therein fixed, not less than five days after the serving of said complaint: Provided, That no complaint shall issue based upon any unfair labor practice occurring more than six months prior to the filing of the charge with the Board and the service of a copy thereof upon the person against whom such charge is made, unless the person aggrieved thereby was prevented from filing such charge by reason of service in the *76armed forces, in which event the six-month period shall be computed from the day of his discharge. Any such complaint may be amended by the member, agent, or agency conducting the hearing or the Board in its discretion at any time prior to the issuance of an order based thereon. The person so complained of shall have the right to file an answer to the original or amended complaint and to appear in person or otherwise and give testimony at the place and time fixed in the complaint. In the discretion of the member, agent, or agency conducting the hearing or the Board, any other person may be allowed to intervene in the said proceeding and to present testimony. Any such proceeding shall, so far as practicable, be conducted in accordance with the rules of evidence applicable in the district courts of the United States under the rules of civil procedure for the district courts of the United States, adopted by the Supreme Court of the United States pursuant to section 2072 of title 28.” 29 U. S. C. §160 (b).
The plain language of this statute indicates that it is directed solely to the administrative procedure established by Congress in the National Labor Relations Act for the resolution of unfair labor practice charges arising under, and processed in accordance with, that Act. Nothing in the statutory language suggests that Congress intended that this 6-month limitations period be applied in any other context.
The National Labor Relations Act was enacted in 1935. 49 Stat. 449. Although § 10 (b) was a part of the Act at that time, in its original form it did not contain a period of limitations. 49 Stat. 453-454. The 6-month limitations period upon which Justice Stewart relies was added to § 10 (b) in 1947. 61 Stat. 146. Six years later, the Court decided the first in a series of cases recognizing that the National Labor Relations Act imposes a duty of fair representation upon unions. See Ford Motor Co. v. Huffman, 345 U. S. 330. In 1967, in Vaca v. Sipes, 386 U. S. 171, the Court clearly held that this duty may be judicially enforced. See generally Hines v. Anchor Motor Freight, Inc., 424 U. S. 554, 563-567.