University of Texas Southwestern Medical Center v. Nassar, Case No. 12-484 (Jun. 24, 2013), the U. S. Supreme Court has directed courts to apply the "but for" test to retaliation claims brought under Title VII. This differs from the standard for assessing status-based discrimination claims that Congress enacted into 42 U.S.C. section §2000e–2(m). That section provides that a plaintiff may establish a case of discrimination based solely on proof that race, color, religion, sex, or nationality was a motivating factor in the employment action. If the employer proves that it would still have taken the same employment action in the absence of a discriminatory motive, it may avoid monetary damages and a reinstatement order.
The Court stated the "but for" test that will now apply to all Title VII retaliation claims as follows: "This requires proof that the unlawful retaliation would not have occurred in the absence of the alleged wrongful action or actions of the employer." Justice Ginsburg's dissenting opinion explained the impact on plaintiffs: "When an event is 'overdetermined,' i.e., when two forces create an injury each alone would be sufficient to cause, modern tort law permits the plaintiff to prevail upon showing that either sufficient condition created the harm. ... In contrast, under the Court’s approach (which it erroneously calls 'textbook
tort law'), a Title VII plaintiff alleging retaliation cannot establish liability if her firing was prompted by both legitimate and illegitimate factors."