The U.S. Supreme Court declined to hear a case that could have resolved a split-circuit dispute over the standard of evidence needed for an employee's retaliation claim to survive summary judgment under the Family and Medical Leave Act.

Many courts, including those at the circuit level, have required that such claims meet the “but for” standard the high court set for Title VII civil rights claims in 2013. That standard requires an employee to show that, but for his exercise of the protected action, he would not have faced retaliation and that the reason for the retaliation was simply a pretext.

Others, however, have adopted the less stringent “motivating factor” or “mixed motive” standard, under which an employee can survive summary judgment by proving a protected activity was but one factor in an employment action. Last year, in a ruling issued while the case was on appeal, the U.S. Court of Appeals for the Eleventh Circuit became the ninth circuit court to adopt the looser standard for other types of claims, according to court filings.