On April 24, 2013, the U.S. Supreme Court will hear arguments from a Texas hospital asking the Court to raise the burden for workers trying to prove employer retaliation. But even before the oral arguments, the Court has received amicus briefs from the U.S. Chamber of Commerce and other advocacy groups throwing their weight behind the hospital’s argument that the Court should adopt a tougher standard for employee-plaintiffs.

In the case, University of Texas Southwestern Medical Center v. Nassar, case number 12-484, the Court will face a broad question that has split the circuit courts: in order to win a retaliation claim under Title VII and other similar statutes, do employees only need to show that the employer had an improper “mixed motive,” or must the employee bear the tougher burden of proving that the employer would not have taken the adverse employment action “but for” an improper motive?

On March 11, 2013, the Chamber and other groups urged the Court to adopt the tougher “but for” standard. Under the more lenient “mixed motive” standard, a disgruntled employee need only prove that the employer’s improper motive was one of multiple reasons for the employment action. In contrast, the more stringent “but for” burden would require the employee to prove that the adverse employment action would not have happened but for the employer’s improper motive.

The Chamber warned that the lower “mixed motive” standard would have significant negative impacts on employer businesses. It argued that the lower burden would allow employees to sue even if an employer “would have made the exact same decision if they had not considered the improper factor.” The Chamber further argues that an employer could essentially be found liable for considering one factor among many in what is already a highly-subjective employment decision, and the lower burden would make it harder for employers to defend against meritless retaliation lawsuits at the summary judgment stage—forcing employers to sign costly settlements just to avoid the risk of a jury trial.

The case highlights a circuit split on the proper standard to apply. While the First, Sixth and Seventh circuits have adopted the tougher “but for” standard, the Fifth and Eleventh circuits have used the more lenient “mixed motive” standard, requiring that an employee only show that an improper motive was one reason, among many, behind the employer’s action. Ultimately, the Court’s ruling later this session should resolve this circuit split and will have a far-reaching impact on employers nationwide.