In a decision announced late last week, Gross v. FBL Financial Services, Inc., the United States Supreme Court held that employees bringing claims under the Age Discrimination In Employment Act (ADEA) have to prove by a preponderance of the evidence, that age was the deciding factor or the "but-for" cause of the challenged adverse employment action, and not just one of several factors that motivated the employer.  The practical effect of the Gross decision is that, unless statutorily overruled by Congress, it will in all likelihood eliminate all so called “mixed-motive” cases under the ADEA, in which age was one of several factors motivating the employer’s decision.    

When the plaintiff in Gross had been demoted and had his job duties reassigned to a younger woman, he sued under the ADEA, which makes it unlawful for an employer to take adverse action against an employee "because of such individual's age."  Following the trial, the federal district court instructed the jury that it must find in favor of the plaintiff if it concludes that he established by a preponderance of the evidence that his age was “a motivating factor” in the employer’s decision.  The jury then rendered a verdict in the plaintiff’s favor.  On appeal, the United States Court of Appeals for the Eighth Circuit reversed the jury’s verdict by holding that the plaintiff had not presented “direct evidence” of discrimination. 

Although the Supreme Court granted certiorari to determine the issue of whether a plaintiff under the ADEA had to present direct evidence of age discrimination in a mixed-motives case in order to shift the burden of persuasion to the employer to show that it would have taken the same action regardless of the illegal age factor, our highest court went beyond that issue, ruling that the burden of persuasion does not shift to the employer under the ADEA but always remains with the employee to demonstrate that age was the “but-for” or the deciding cause in the adverse employment decision.  In so doing, the Supreme Court claimed it was relying on the plain language of the ADEA which makes it unlawful for an employer to discriminate “because of” age. 

Although the Gross decision is viewed as a major victory for employers in potentially warding off ADEA suits, observers believe that Congress will act to amend the ADEA to allow for mixed-motive cases.  Reacting to the decision, Senate Judiciary Chairman Patrick Leahy, D-Vt., said, "[i]n the Supreme Court's decision today, five justices acted to disregard precedent and ignore the plain reading and common understanding of the statute that Congress passed to protect Americans from discrimination based on their age.  It is even more troubling that these five justices decided to go further than the question presented to the Court."