President Donald Trump joined his personal attorney on Monday in asking a federal judge to order into arbitration a lawsuit filed by his alleged former mistress, a move that would put the proceedings behind closed doors rather than in front of a jury.

“This motion seeks to enforce the arbitration provision in the Settlement Agreement,” submitted Brent Blakely, the lawyer representing Michael Cohen, himself representing President Trump. “The strong policy favoring arbitration set forth by Congress in the Federal Arbitration Act (‘FAA’) dictates that this motion be granted.”

The new court filing also notified U.S. District Court Judge James Otero that “Defendant Donald J. Trump hereby joins in defendant Essential Consultants, LLC’s motion to compel arbitration.” Essential Consultants, LLC is the name of the Delaware-based shell corporation through which Cohen passed $130,000 in October 2016, for which adult film star Stephanie Clifford—better known as Stormy Daniels, her professional name—exchanged her silence about an alleged affair with Trump in 2006.

Daniels’ attorney, Michael Avenatti, tweeted that he will “vigorously oppose” the motion, which he described as an attempt to have the proceedings “hidden from the American public.”

“This is a democracy and this matter should be decided in an open court of law owned by the people,” Avenatti continued, adding the hashtag “#sunlight”.

The original suit, filed in March, seeks to officially nullify a non-disclosure agreement signed by Daniels in the final days of the 2016 presidential campaign. Daniels claims that the agreement was not binding because Trump himself did not sign it.

In a memo filed in support of the motion to compel arbitration, Cohen’s attorney argues that the contract between Daniels and Essential Consultants, LLC can be enforced regardless of whether Trump—or, as he was designated in the hush agreement, “David Dennison”—signed the agreement.

“Clifford and EC signed the Settlement Agreement, and Clifford accepted $130,000 in consideration from EC, despite not receiving a signature from Mr. Trump,” Blakeley wrote. “Then, over the course of the next sixteen (16) months, Clifford did not at any time: reject the Settlement Agreement; offer to return or return the $130,000; or assert that the Settlement Agreement is unenforceable because it was not signed by Mr. Trump, or for any other reason.”