In a troubling decision for employers, the United States Supreme Court has endorsed the so-called "cat's paw" doctrine of employment discrimination. Under the "cat's paw" doctrine – named for a fable in which a monkey flatters a cat into extracting roasted chestnuts from an open fire and results in the cat burning its paws in the process – an employer may be held liable for the discriminatory animus of a supervisor who influenced, but did not make, the adverse employment decision.

Staub v. Proctor Hospital involved a claim of military status discrimination in violation of the Uniformed Services Employment and Reemployment Rights Act ("USERRA"). Vincent Staub, a medical imaging technician and Army Reservist, alleged that his two supervisors were hostile to his military obligations and were out to "get rid of him." Mr. Staub claimed that one of his supervisors improperly disciplined him for leaving his work area and issued him a written directive to check in with his supervisors when he was not working with patients, and that the other supervisor falsely reported to the VP of Human Resources that Mr. Staub subsequently violated the written directive. The VP of Human Resources (the "cat's paw"), relying upon the reported violation and her own review of Mr. Staub's personnel file, made the decision to terminate Mr. Staub. Despite Mr. Staub's insistence that the violation was fabricated and that his supervisors were improperly motivated by hostility towards his military obligations, the VP of Human Resources did not follow up with Mr. Staub's supervisors to investigate further. Mr. Staub subsequently filed a lawsuit under USERRA, claiming that his supervisors (but not the decisionmaker) were motivated by hostility to his military obligations, and that their actions unlawfully influenced the termination decision.  

After a jury verdict in favor of Mr. Staub, which was later reversed by the Seventh Circuit Court of Appeals, the Supreme Court accepted review of the case to consider the circumstances under which an employer can be liable for "cat's paw" discrimination. Relying on general tort law causation principles, the court held that if a supervisor performs an act motivated by unlawful discrimination that is intended by the supervisor to cause an adverse action, and the act is a proximate cause of the adverse action, the employer is liable for discrimination. However, the Court further held that if an employer can establish that it undertook an independent investigation and determined that the adverse action was entirely justified, apart from and without considering the biased supervisor's actions, the employer will avoid liability.

In Staub, the Court determined that there was sufficient evidence to allow the jury to decide the case. Staub presented evidence that both supervisors were motivated by hostility towards Mr. Staub's military obligations (including comments that other workers had to "bend over backwards" due to Mr. Staub's military obligations and that such obligations were a "waste of taxpayers' money"), that the supervisors' actions were causal factors underlying the decision to terminate Mr. Staub and that both supervisors intended to cause Mr. Staub's termination.

While Staub involved discrimination on the basis of military status, its rationale will likely be applied to discrimination covered by Title VII and other laws, which may make it more difficult for employers to prevail in discrimination lawsuits or get lawsuits resolved on summary judgment. The Staub holding invites several fact-intensive determinations – including an analysis of the motivations of all supervisors involved in the termination decision and whether any improper actions can be said to have reasonably caused the ultimate adverse action – which require resolution by a jury and which are not generally susceptible to resolution prior to trial.

Staub also emphasizes the critical importance of conducting thorough, independent investigations into allegations of biased employment actions. To prevent a biased action from unlawfully tainting an adverse employment action, Staub makes clear an employer must independently review and make a determination regarding the proposed action without relying on improper conduct by supervisors.