The United Steelworkers of America (USWA) (defendant) and Kaiser Aluminum & Chemical Corporation (Kaiser) (defendant) entered into a collective-bargaining agreement in 1974. The agreement applied to 15 facilities and contained an affirmative-action plan that was designed to address racial disparities in Kaiser’s craftwork positions. Prior to the agreement, Kaiser’s craftwork force was almost exclusively white. This was a result of Kaiser’s practice of only hiring craftworkers who had prior craft experience. Black workers had been excluded from craft unions in the past, and few black workers could meet this requirement. Pursuant to the agreement, Kaiser established a training program for production workers to fill skilled craftworker positions. At least 50 percent of the trainee positions were reserved for black craftworkers until the percentage of black craftworkers approximated the percentage of black workers in the local labor force. Otherwise, the trainee positions were filled on the basis of seniority. Brian Weber (plaintiff) was a white production worker who was not selected for a trainee position, even though Weber had more seniority than some of the black workers who were selected. Weber filed a class-action lawsuit against Kaiser and USWA, alleging that the affirmative-action plan discriminated against white employees in violation of Title VII of the Civil Rights Act (Title VII), 42 U.S.C. § 2000e. The trial court ruled in favor of Weber. Kaiser and USWA appealed to the United States Court of Appeals for the Fifth Circuit, which affirmed. Kaiser and USWA petitioned the United States Supreme Court for review.