Appellant Ralph J. Miller appeals from a summary judgment in an action under 39 U.S.C. § 1208(b) (1980)1 for breach of contract against the United States Postal Service ("Postal Service"), and for breach of duty of fair representation against the National Rural Letter Carrier's Association (the "Union"). This joint cause is commonly referred to as a "hybrid" suit. See, e.g., Reed v. United Transp. Union, 488 U.S. 319, 327, 109 S. Ct. 621, 627-28, 102 L. Ed. 2d 665 (1989). We affirm the district court's judgment.

Appellant, a rural carrier, lost his job at the Postal Service on May 21, 1986. As a member of the collective bargaining unit, he filed a grievance under the collective bargaining agreement between the Union and the Postal Service. The matter culminated in arbitration, in which the arbitrator found that the Postal Service fired appellant without just cause, and ordered reinstatement and lost earnings. Approximately one month after this ruling, the Postal Service reinstated appellant but refused to afford him back pay. The Postal Service based this refusal on appellant's alleged failure to mitigate his damages by attempting to obtain other employment during the thirteen-month period of suspension as required by the Postal Service's Employee and Labor Relations Manual (the "Manual").

Consequently, appellant filed a new grievance for back pay which proceeded through the various contractual steps until it reached national arbitration on July 28, 1989. In addition, on July 10, 1990, appellant filed the present action in the United States District Court for the District of New Hampshire. The Union subsequently withdrew the grievance from arbitration.

Appellant initially proceeded pro se in his federal court action against the Postal Service and the Union.2 A series of amendments followed his original complaint. Essentially, he alleged that: (1) the Postal Service failed to abide by the arbitration award, and the Manual's mitigation requirements conflicted with the provisions of the collective bargaining agreement; and (2) the Union was "either unwilling or unable to recover [his] money."

The Postal Service counterattacked with its own motion for summary judgment, which the Union joined. The motion asserted that: (1) the collective bargaining contract incorporated the Manual by reference; (2) the Manual required a suspended employee to mitigate damages by seeking employment during suspension or discharge; and (3) appellant failed to mitigate his damages. Additionally, the Union asserted that its decision to withdraw appellant's grievance for back pay "was made for rational, nondiscriminatory reasons."

Appellant, by this time represented by counsel, retorted that the Postal Service was "not entitled to a judgment as a matter of law because the defense now asserted was not raised in the underlying arbitration." With respect to the Union, appellant maintained that it had treated his claim "in a perfunctory manner" and that this conduct, coupled with the three-year delay during which it failed to inform appellant of alternate modes of relief, amounted to a breach of the Union's duty of fair representation when it withdrew the grievance.

The district court's summary judgment for the Postal Service is narrowly tailored and deserves our approval. To succeed in a hybrid breach of contract and fair representation claim, appellant must establish not only that the employer breached the contract, but also that his union breached its duty of fair representation. Teamsters v. Terry, 494 U.S. 558, 564, 110 S. Ct. 1339, 1344, 108 L. Ed. 2d 519 (1990); Hines v. Anchor Motor Freight, Inc., 424 U.S. 554, 570-71, 96 S. Ct. 1048, 1059-60, 47 L. Ed. 2d 231 (1976). These claims are "inextricably linked," Demars v. General Dynamics Corp., 779 F.2d 95, 97 (1st Cir.1985), and failure to prove either one of them results in failure of the entire hybrid action. See DelCostello v. Teamsters, 462 U.S. 151, 164-65, 103 S. Ct. 2281, 2290-91, 76 L. Ed. 2d 476 (1983).

The district court found no violation of the Union's duty toward appellant, and we agree. A Union breaches this duty "only when [its] conduct toward a member of the collective bargaining unit is arbitrary, discriminatory, or in bad faith." Vaca v. Sipes, 386 U.S. 171, 190, 87 S. Ct. 903, 916, 17 L. Ed. 2d 842 (1967); Williams v. Sea-Land Corp., 844 F.2d 17, 19 (1st Cir.1988). The Supreme Court explained that a union's actions are arbitrary "only if, in light of the factual and legal landscape at the time of the union's actions, the union's behavior is so far outside a 'wide range of reasonableness' as to be irrational." Air Line Pilots Ass'n Int'l v. O'Neill, --- U.S. ----, ----, 111 S. Ct. 1127, 1130, 113 L. Ed. 2d 51 (1991) (citations omitted). Courts may not substitute their own views for those of the union. "[A]ny substantial examination of a union's performance ... must be highly deferential," id. --- U.S. at ----, 111 S. Ct. at 1135, because of the well-recognized need to allow unions ample latitude in the performance of their representative duties. See Steelworkers v. Rawson, 495 U.S. 362, 374, 110 S. Ct. 1904, 1912, 109 L. Ed. 2d 362 (1990); Vaca, 386 U.S. at 191-93, 87 S.Ct. at 917-18. Thus, we have held that a union's mere negligence or erroneous judgment will not constitute a breach of the duty of fair representation. Condon v. United Steelworkers Local 2944, 683 F.2d 590, 594 (1st Cir.1982). We also allow the union great latitude in determining the merits of an employee's grievance and the level of effort it will expend to pursue it. Torres-Matos v. St. Lawrence Garment Co., 901 F.2d 1144, 1148 (1st Cir.1990); Williams, 844 F.2d at 21.

Accordingly, failure to take a grievance to arbitration constitutes a breach of the duty of fair representation only when the union's otherwise good faith decision is arbitrary. See Colon-Velez v. Puerto Rico Marine Management, Inc., 957 F.2d 933, 941 (1st Cir.1992); see also Vaca, 386 U.S. at 191, 87 S.Ct. at 917 (employees have no absolute right to have grievance taken to arbitration).

The undisputed facts establish that the Union initially supported appellant's grievance regarding his back-pay claim. It processed the grievance through the various contractual steps up to national arbitration. Although the Union knew of appellant's failure to mitigate, the Union believed that a genuine issue existed regarding whether the mitigation requirements were "punitive, unreasonable and in conflict with other provisions of the National Agreement." It thus sought arbitration of appellant's claim and continued to investigate the matter. As a result of this investigation, the Union discovered that several arbitrators had found mitigation requirements valid. Accordingly, it decided that it was in everyone's best interests to withdraw the grievance from arbitration.3 Before doing so, however, it attempted, unsuccessfully, to negotiate a settlement with the Postal Service. On November 8, 1990, the Union withdrew the grievance.

Given these undisputed facts, we cannot conclude that the Union's actions were irrational. Furthermore, nothing in the record intimates that the Union acted in a perfunctory or arbitrary manner or in bad faith. If anything, the record exhibits diligence and an attempt to make the best out of a difficult situation. If the Union failed, it was not through lack of effort, but rather because appellant's claim lacked merit.

Finally, at oral argument appellant argued principally that the Union violated its duty of fair representation by failing to properly advise him of the Manual's mitigation requirements. This is a new argument, never raised in the district court. Appellant's change in direction has been a recurrent theme throughout this litigation. See, e.g., Miller v. United States Postal Serv., 792 F. Supp. 4, 6 n. 4 (D.N.H.1992). If the argument was mistakenly overlooked during the pro se stages of the case, appellant had ample opportunity, once represented by counsel, to correct any earlier deficiencies. It is now too late to do so; we cannot consider issues raised for the first time on appeal. G.D. v. Westmoreland Sch. Dist., 930 F.2d 942, 950 (1st Cir.1991); Johnston v. Holiday Inns, Inc., 595 F.2d 890, 894 (1st Cir.1979).4

After considering the other issues raised by appellant, we find them equally insubstantial. Thus, we need go no further; as appellant failed to make a case against the Union, the symbiotic nature of the hybrid action requires that we also reject the action against the Postal Service.

Affirmed.

Costs to appellees.