Constitutional law professors from some of the nation’s most prestigious law schools say former President Donald Trump should not escape liability for his role in the Jan. 6, 2021, attack on the Capitol.

“Trump … seeks to invoke the immunity doctrine as an absolute shield from damages liability for unofficial conduct that allegedly sought to serve his own private interests as a candidate for office by forcibly interfering with the constitutionally mandated functions of Congress,” argued University of Michigan Law School professor Evan Caminker, Harvard Law School’s Vicki Jackson and Daphna Renan, Fordham University School of Law professor Andrew Kent, Sheldon Nahmod from Chicago-Kent College of Law and Peter Shane from the Ohio State University Moritz College of Law in an amicus brief filed Friday with the U.S. Court of Appeals for the District of Columbia Circuit.

The brief supports two Capitol police officers and 11 members of Congress in their Ku Klux Klan Act claims against Trump, the Proud Boys and their leader, Enrique Tarrio, the Oath Keepers and Warboys. Several original defendants, including Trump’s adult son Donald Trump Jr. and his lawyer Rudy Giuliani, have since been dismissed from the suit.

The professors argue binding U.S. Supreme Court precedent and separation of powers principals mandate the denial of immunity to the former president “for his personal efforts to incite a crowd to forcibly disrupt congressional proceedings and infiltrate the ‘People’s House.’”

Trump, meanwhile, said he was engaged in a political speech in his role as president and should therefore be protected from the lawsuit.

“A U.S. district court has no more authority to penalize the president for his use of his bully pulpit than the president has in having the U.S. Marshall Service arrest a judge because of a disfavored legal decision,” wrote Trump’s attorney Jesse Binnall from the Binnall Law group.

But the professor’s brief points to parts of Judge Amit P. Mehta’s February opinion in the U.S. District Court for the District of Columbia that found the speech Trump made to his supporters just before the attack amounted to “words of incitement not protected by the First Amendment.”

Trump appealed that ruling, but oral arguments have not yet been scheduled.

“The presidential immunity doctrine is designed to prevent the judicial branch from undermining the president’s capacity to discharge fully and fearlessly his constitutionally assigned roles,” the new amicus brief reads. “But Trump fails to point to any official responsibility that his alleged efforts to incite violence against a co-equal branch of government could have been advancing.”

The law professors’ brief was authored by Brianne Gorod, Elizabeth Wydra and Charlotte Schwartz from the Constitutional Accountability Center.

The progressive-leaning group’s president, Wydra, said they wanted to make clear that Trump should not be able to “evade accountability for his role in the January 6th insurrection.”

“No one is above the law,” she said.