On June 18, 2009, the United States Supreme Court issued an important decision which substantially limits the manner in which an employee may prove a claim of age discrimination under the Age Discrimination in Employment Act of 1967 (ADEA). In the case of Gross v. FBL Financial Services, Inc., the court held that in order to prevail on an age discrimination claim under the ADEA, an employee must now prove that age was the “but-for” cause of the challenged employment action. In reaching this conclusion, the court rejected the argument that an employee could prove such a claim by merely offering proof that age was one of the motivating factors for the employment action.

Gross began working for FBL in 1971. As of 2001, he held the position of claims administration director. In 2003, when he was 54 years old, Gross was reassigned to a coordinator position and many of his former job duties were transferred to a newly created manager position which was given to a younger employee. Gross filed suit against FBL, claiming that his job reassignment violated the ADEA. At trial, Gross presented evidence that his reassignment was based at least in part on his age -- although there was also evidence that his reassignment was a part of a corporate restructuring. Thus, Gross presented his claim as a “mixed-motive” case, arguing that he should prevail under the ADEA on the grounds that age was one of the motivating factors for his reassignment. The jury agreed and returned a verdict in favor of Gross. FBL appealed, and the case eventually reached the Supreme Court.

The ADEA prohibits employers from taking an adverse action against an employee “because of such individual’s age.” The court focused on the plain meaning of this language in concluding that the ADEA requires an employee to prove that “but for” his or her age, the employer would not have taken the challenged adverse action against the employee. In other words, an employee must now prove that age was the sole and determinative reason for the adverse action -- as opposed to one motivating factor among others. As a result, the court’s holding effectively eliminates the “mixed-motive” theory in ADEA cases. Moreover, the court held that the burden of persuasion does not shift to the employer to prove that its action was based on some non-discriminatory reason. The burden of persuasion remains with the employee throughout the action.

In reaching this decision, the Supreme Court distinguished the ADEA from Title VII of the Civil Rights Act of 1964, which prohibits discrimination against individuals on the basis of race, color, gender, national origin, and religion. The court recognized that with the Civil Rights Act of 1991, Congress specifically amended Title VII to allow mixed-motive type discrimination claims. However, the court observed that Congress did not make similar amendments to the ADEA. Therefore, the court concluded that Congress intended not to allow mixed-motive claims to be brought under the ADEA.

With this decision, the Supreme Court has thus made it significantly more difficult for employees to prove age discrimination claims against employers. Unfortunately, however, this favorable outcome for employers may prove to be short-lived if Congress now seeks to amend the ADEA. Congress has shown a willingness to nullify pro-employer court decisions, as it recently did with the Ledbetter Act. Therefore, and while the Supreme Court’s decision is certainly good news, employers should remain watchful.