A U.S. senator, in a rare move, joined business and employee rights advocates to weigh in on the next battle poised to be heard by the Supreme Court over the arbitration agreements proliferating in corporate America.

In his first friend-of-the-court brief as counsel of record, Sen. Sheldon Whitehouse, a  Rhode Island Democrat, pressed for the right of independent contractors to litigate labor disputes in court in New Prime v. Oliveira. Oral arguments in the case are scheduled for Oct. 3. Groups, including the U.S. Chamber of Commerce and the National Employment Law Project, also have weighed in on the importance of the outcome of the case.