In the Clayton v. International Union case of 1980, the Supreme Court ruled in favor of Robert Clayton, a member of United Automobile Workers (UAW) who was fired from his job at Bendix Corporation for allegedly falsifying time cards. The UAW initially refused to pursue grievance procedures on behalf of Clayton due to lack of merit in his claim and instead supported Bendix's decision. However, after an internal union appeal process, it reversed its stance but failed to reinstate him promptly leading to financial hardship for Clayton. He then sued the UAW under section 301(a) Labor Management Relations Act alleging breach of duty by failing to fairly represent him during arbitration proceedings with Bendix Corp., which led to loss wages and benefits. The court held that while unions have broad discretion in representing their members' interests during collective bargaining and dispute resolution processes; they are still obligated under federal labor law not only act honestly and in good faith but also avoid arbitrary conduct when dealing with individual members' grievances against employers. Furthermore, if a union fails this duty causing harm or injury such as lost wages or employment opportunities; affected workers can sue them directly for damages even without exhausting all available internal remedies within their respective unions.

In the dissenting opinion for Clayton v. International Union, United Automobile, Aerospace & Agricultural Implement Workers of America et al., Justice Brennan disagreed with the majority's interpretation of Section 301(a) of the Labor Management Relations Act. He argued that Congress intended to provide a federal forum for all suits involving collective bargaining agreements and not just those alleging contract violations. The majority’s narrow reading would exclude many cases from federal jurisdiction which could lead to inconsistent state court interpretations undermining national labor policy uniformity. Furthermore, he contended that even if Clayton's claim was considered tortious rather than contractual in nature, it should still fall under Section 301(a) as it arose out of a dispute over union representation rights - an issue central to any collective bargaining agreement.