On June 24, 2013, the United States Supreme Court decided University of Texas Southwestern Medical Center v. Nassar, in which the Court held that claims of retaliation must be proved using a “but for” standard as opposed to the seemingly lower “motivating factor” standard of causation.
The plaintiff had argued that in order to prevail on his claim of retaliation, he had to show that his engaging in protected activity was a motivating factor in his termination. The motivating factor standard, which applies to claims of status discrimination (e.g., sex, race, religion, national origin and disability), provides that to prevail on an employment discrimination claim, an employee need only “show that the motive to discriminate was one of the employer’s motives, even if the employer also had other, lawful motives for the decision.”
Based upon its review of the language of Title VII, the Supreme Court stated that the motivating factor standard did not apply to claims of retaliation, and that, instead, traditional principles of but-for causation applied.
<p <Although in principle the "but-for" standard is more stringent than the motivating factor standard, it is important to note that the standard is not synonymous with the "sole factor" standard, which is the most difficult one to satisfy. Moreover, practically speaking, the differences between the but-for standard and the motivating factor standard might only surface in a few circumstances, limited by the fact that a court has yet to clearly distinguish the standards in practice.
Consequently, it appears unlikely that the Court’s decision will have any significant impact on a plaintiff’s ability to prove unlawful retaliation.