A “cat's-paw” theory of unlawful employment discrimination may arise where an employee argues that a biased non-decision-maker has influenced an unbiased decision-maker to take action that he or she otherwise would not have taken. On March 1, 2011, in Staub v. Proctor Hospital, the United States Supreme Court spoke for the first time on the issue, acknowledging the cat's-paw theory of liability and setting out a broad framework to be applied in such cases.

Prior to having his employment terminated, the plaintiff in Staub had been a technologist at the defendant Proctor Hospital (“Proctor”) and a member of the United States Army Reserve. He filed suit against Proctor, alleging that he was discharged based upon his military status, in violation of the Uniformed Services Employment and Reemployment Rights Act (“USERRA”). The hospital’s Vice-President of Human Resources had made the decision to terminate the plaintiff’s employment. Although the plaintiff conceded that that this senior employee had harbored no discriminatory animus on account of his military status, he contended that – under the “cat's paw” theory of liability – the anti-military bias of his immediate supervisors influenced the decision to terminate his employment, thus violating USERRA.