Employer sued the union and its workers for RICO violations, claiming that the workers and the union had conspired to fraudulently furnish timesheets reporting hours that were not actually worked, causing employer to overpay the workers by $5.3 million. Over a strong dissent, this opinion holds that the suit is preempted by section 301 of the LMRA because the collective bargaining agreement must be interpreted in order to determine whether the challenged hours were properly billed even though the workers weren’t present at the employer’s place of work at the time. Federal as well as state law claims are precluded by section 301 when interpretation of the CBA is required. Also, the CBA contained a broad arbitration provision which covered the employer’s RICO claims.