On June 24, 2013, the U.S. Supreme Court held that plaintiffs pursuing retaliation claims under Title VII of the Civil Rights Act must establish that the alleged adverse employment action would not have occurred "but for" unlawful retaliation. Univ. of Tex. Sw. Med. Ctr. v. Nassar, 12-484 (June 24, 2013). In reaching this 5-4 decision, the Court concluded that the "motivating factor" standard typically applied in Title VII actions only applies to discrimination claims, not retaliation claims.

In Nassar, the plaintiff, a physician employed by the University of Texas Southwestern Medical Center ("University"), accused his supervisor of racial and religious bias. Subsequently, the plaintiff arranged to resign from his position at the University and become employed directly by the hospital, which would result in a change of supervisors. But, University officials allegedly prevented him from being hired by the hospital in retaliation for his earlier discrimination claims.

The University, arguing that the "but-for" standard of causation applied to Title VII retaliation claims, asserted that the plaintiff would not have been hired by the hospital even in the absence of any alleged retaliation because the hospital’s affiliation agreement with the University required that all staff physicians also be members of the University faculty. The plaintiff argued that retaliation claims brought under Title VII require that retaliation was merely a "motivating factor" for the adverse employment action, rather than its but-for cause. Following trial, a jury ultimately found for the plaintiff on his retaliation claim. On appeal, the Fifth Circuit affirmed, holding that retaliation claims brought under Title VII only require a showing that retaliation was a motivating factor for the adverse employment action.

The Supreme Court reversed, holding that retaliation claims under Title VII must be proved according to traditional principles of but-for causation, not the lessened "motivating factor" test applicable to status-based discrimination. In reaching this decision, the Court focused on the text and structure of Title VII. The Court emphasized that the motivating factor provision of Title VII—which provides that "an unlawful employment practice is established when the complaining party demonstrates that race, color, religion, sex, or national origin was a motivating factor for any employment practice"—omits reference to any unlawful employment practices based on alleged retaliation. Further, the Court noted that when the motivating factor provision was added to Title VII in 1991, Congress inserted the provision within the section of the statute dealing only with status-based discrimination, and not in the separate sections dealing with retaliation claims or all claims of unlawful employment practices.

In this regard, the Court deemed significant the fact that an employee’s opposition to employment discrimination (including the pursuit of a complaint alleging employment discrimination) is covered by a separate and subsequent section of Title VII, which prohibits employers from retaliating against an employee because of his or her engagement in protected activity. The Court also relied on its 2009 decision in Gross v. FBL Financial Services, Inc., where it held that the Age Discrimination in Employment Act, which also prohibits employers from taking adverse employment decisions because of an individual’s age, requires proof that the prohibited criterion was the but-for cause of the prohibited conduct. Thus, the Court ultimately concluded that Title VII retaliation claims require proof that the unlawful retaliation would not have occurred in the absence of the alleged wrongful action or actions of the employer.

The Court rejected the plaintiff’s arguments that retaliation for complaining about status-based discrimination is itself status-based discrimination. Not only did the Court find this argument inconsistent with the plain language of the motivating-factor provision and the design and structure of Title VII as a whole, but the Court also rejected the notion that the phrase, "race, color, religion, sex, or national origin" in the motivating factor provision is the textual equivalent of "retaliation."

With claims of retaliation being raised with ever-increasing frequency—indeed, in terms of numbers of claims filed, retaliation complaints currently surpass all other Title VII claims except racial discrimination claims—Nassar is an important decision for employers.