The U.S. Supreme Court has clarified the standards under which an employer can be liable for discrimination under the so-called "cat's paw" theory of liability in a discrimination claim. See Staub v. Proctor Hospital, No. 09-400 (March 1, 2011). The Court held that if a supervisor performs an act motivated by unlawful animus and intends to cause an adverse employment action, the employer is liable if the supervisor's act is a proximate cause of the adverse decision even if the decision maker did not share the supervisor's animus. The decision was issued in a case brought under the Uniformed Services Employment and Reemployment Rights Act (USERRA), but its holding will likely be applied in cases under Title VII and other discrimination statutes.

The issue in Staub was whether an employer is liable for unlawful discrimination when a decision maker relies in part on information tainted by the discriminatory animus of a lower level supervisor, and in part on the decision maker's independent investigation. Staub's immediate supervisor and second level supervisor both harbored unlawful animus based on Staub's military service and falsely accused him of performance deficiencies. The decision maker was at a higher level than those two supervisors. The decision maker investigated the alleged performance deficiencies, rejected Staub's objection that the supervisors' accusations were motivated by unlawful animus, and also considered Staub's personnel file and other information. The decision maker decided to fire Staub and he sued, alleging a violation of USERRA.