Harvard Law professor emeritus Alan Dershowitz said Democrats have virtually no chance of successfully impeaching and removing President Donald Trump before Inauguration Day on Jan. 20.

“The case cannot come to trial in the Senate. Because the Senate has rules, and the rules would not allow the case to come to trial until, according to the majority leader, until 1 p.m. on January 20th, an hour after President Trump leaves office,” Dershowitz said in a Fox Business interview on Sunday.

Dershowitz, who defended Trump during the Senate impeachment trial about a year ago, suggested that the Constitution does not allow for impeaching a former president.

“And the Constitution specifically says, ‘The President shall be removed from office upon impeachment.’ It doesn’t say the former president. Congress has no power to impeach or try a private citizen, whether it be a private citizen named Donald Trump or named Barack Obama or anyone else,” he said.

It comes as House Democrats have proposed articles of impeachment after Trump made a speech to protesters near the Capitol. Some critics have claimed Trump incited the crowd into violence before a group stormed the Capitol building.

Trump told the crowd beforehand that their protest shows “the kind of pride and boldness that they need to take back our country” and “let us walk down Pennsylvania Avenue.” The president did not tell the protesters to breach the Capitol or commit acts of violence and later condemned them.

At one point, Trump told the protesters to “peacefully and patriotically make your voices be heard.”

Another Trump defender during the House impeachment inquiry, law professor Jonathan Turley, explained that impeaching Trump over his speech would set a dangerous precedent.

“When I testified in the impeachment hearings of Trump and Bill Clinton, I noted that an article of impeachment does not have to be based on any clear crime but that Congress has looked to the criminal code to weigh impeachment offenses,” he said in an opinion piece. “For this controversy now, any such comparison would dispel claims of criminal incitement. Despite broad and justified condemnation of his words, Trump never actually called for violence or riots. But he urged his supporters to march on the Capitol to raise their opposition to the certification of electoral votes and to back the recent challenges made by a few members of Congress.”