In Price Waterhouse v. Hopkins, 490 U.S. 228, 258, 268-69 (1989), a plurality of this Court held that the discrimination provision of Title VII of the Civil Rights Act of 1964, 42 U.S.C. § 2000e-2(a), requires a plaintiff to prove only that discrimination was "a motivating factor" for an adverse employment action. In contrast, Gross v. FBL Financial Services, Inc., 557 U.S. 167, 179-80 (2009), held that the Age Discrimination in Employment Act of 1967 (ADEA), Pub. L. 90-202, 81 Stat. 602, requires proof that age was "the but-for cause" of an adverse employment action, such that a defendant is not liable if it would have taken the same action for other, non-discriminatory reasons. The courts of appeals have since divided 3-2 on whether Gross or Price Waterhouse establishes the general rule for other federal employment statutes, such as Title VII’s retaliation provision, that do not specifically authorize mixed-motive claims.
The question presented is:
Whether Title VII's retaliation provision and similarly worded statutes require a plaintiff to prove but-for causation (i.e., that an employer would not have taken an adverse employment action but for an improper motive), or instead require only proof that the employer had a mixed motive (i.e., that an improper motive was one of multiple reasons for
the employment action).