1. Does a union have the general democratic right to favor loyal members and disfavor disloyal members when negotiating collective bargaining agreements with an employer?
2. Was the IAM able to prove that it had an independent rational basis supporting its decision to deny the plaintiffs Eastern seniority, in that they had resigned from Eastern prior to being hired by Trump Shuttle?

[Shuttle mechanics employed by Eastern Airlines "transitioned" in 1989 from Eastern to the successor carrier Trump Shuttle, which purchased the shuttle operation in bankruptcy proceedings. In 1990, these mechanics voted out the International Association of Machinists (IAM) union as their representative and chose a rival union, the Aircraft Mechanics Fraternal Association (AMFA). U.S. Airways acquired rights to the shuttle routes in 1992 with "single carrier status."
The IAM, which represented U.S. Air mechanics, resumed its status as the representative of former Eastern mechanics. In March 1998, U.S. Air announced its intention to integrate the shuttle workforce with its regular work force. The IAM negotiated seniority status for the former Eastern mechanics as of the date they started working at Trump Shuttle, asserting that they had resigned from Eastern prior to accepting employment at Trump. The former Eastern mechanics sued the IAM, contending that the union had breached its duty of fair representation by failing to bargain for full seniority rights for them based on their Eastern Airlines service. A jury found for the plaintiffs, and the union appealed.]
MESKILL, C. J….
"The statutory duty of fair representation was developed [decades] ago." Vaca v. Sipes, 386 U.S. 171, 177 (1967). "[A] union breaches this duty … when its con duct toward a member of the bargaining unit is arbitrary, discriminatory, or in bad faith." Marquez v. Screen Actors Guild, 525 U.S. 33, 44 (1998). Put differently, a breach occurs when a union fails to "serve the interests of all members without hostility or discrimination toward any, exercise its discretion with complete good faith and honesty, [or] avoid arbitrary conduct." Vaca, 386 U.S. at 177. "[A] union may not, without a legitimate purpose, take action favoring some of its members at the expense of others." Teamsters Local Union No. 42 v. NLRB, 825 F.2d 608, 611 (1st Cir. 1987) (citing Laborers and Hod Carriers Local No. 341 v. NLRB, 564 F.2d 834, 840 (9th Cir. 1977). Additionally, "a union violates [its duty] when it causes an employer to discriminate against employees on arbitrary, hostile, or bad faith grounds." Barton Brands, 529 F.2d at 799.
Although our review of a union's collective bargaining "must be highly deferential [and must] recogniz[e] the wide latitude that [unions] need for the effective performance of their bargaining responsibilities," Airline Pilots Association v. O'Neill, 499 U.S. 65, 78 (1991), "a union may not juggle the seniority roster for no reason other than to advance one group of employees over another" or to punish a disfavored group, Rakestraw v. United Airlines, 981 F.2d 1524, 1535 (7th Cir. 1992) ("[W]hen a union attempts to prefer [one group of] workers based solely on [their loyalty to their guild]," it has breached its duty.). Finally, a union is not permitted to ignore its own policies to punish a minority group within the union. Nellis v. Air Line Pilots Association, 815 F. Supp. 1522, 1533 (E.D. Va. 1993).
The jury found that IAM violated these principles. Rather than treating plaintiffs as having transitioned from Eastern-a policy IAM announced in the Eastern bankruptcy proceeding-IAM instead opted to treat them as having resigned in order to strip them of their seniority status for no reason other than animus….
In this case, there was ample evidence, when viewed in the aggregate, to support the verdict. IAM claimed at trial that its motivation for stripping plaintiffs of their Eastern seniority was their having resigned from Eastern. This claim was belied by the position it had taken during the Eastern bankruptcy proceeding that plaintiffs were to be considered as merely having transitioned from Eastern to Trump. Once plaintiffs showed that IAM's purported neutral motivation was pretextual, they only needed to convince the jury that the single other motivation suggested by either party-animus as a result of plaintiffs' association with AMFA-was the reason for IAM's adverse decision.

Plaintiffs met this burden by producing various pieces of evidence pointing to this rationale. For instance, at least one plaintiff testified to personal knowledge of the acrimony between IAM and AMFA. Further, at least one IAM official testified as to the hostility between the groups. In addition, with respect to plaintiffs themselves, the minutes of an IAM local lodge stated that plaintiffs "voted for AMFA. IAM will now go for their jobs." Similarly, various IAM union members petitioned IAM officials not to accord plaintiffs their Eastern seniority because they voted in favor of AMFA. Viewing this evidence in the aggregate and in light of Attorney Lee Seham's corroborating testimony that IAM officials were themselves hostile towards those associated with AMFA, the jury reasonably could have believed that IAM was swayed by the sentiments expressed by its members and officials.