Impeachment manager Adam Schiff, D-California, arrives at the U.S. Capitol in Washington for the start of the Senate impeachment trial against President Donald Trump on Jan. 21, 2020. Photo: Diego M. Radzinschi/ALM

House Intelligence Committee chairman and former federal prosecutor Adam Schiff on Wednesday kicked off the House's arguments for the removal of Donald Trump by taking a shot at the president's lawyers.

The president's legal team has argued that abuse of power isn't an impeachable offense, and that Trump must have committed a crime to be removed from office. It's a legal argument that constitutional scholars have rejected, and on Wednesday, Schiff did as well.

"You will appreciate there is no serious dispute about the facts underlying the president's conduct," Schiff told the Senate chamber. "And this is why you will hear the president's lawyers make the astounding claim that you can't impeach a president for abusing the powers of his office. Because they can't seriously contest that that is exactly—exactly—what he did."

"And so they must go find a lawyer, somewhere," Schiff continued. "Apparently they could not go to their own attorney general. It was just reported in a memo he wrote as part of the audition for attorney general, which opined a president could be impeached for abusing the public trust."

The House Intelligence Committee chairman appeared to be referring to a report in the New York Times that Attorney General William Barr had written in an unsolicited memo to the Justice Department in 2018 that abuse of power is impeachable.

"Couldn't go to Bill Barr for that opinion, couldn't even go to Jonathan Turley, their expert in the House for that opinion, no," Schiff said Wednesday. "They had to go outside of those experts, outside of the constitutional law to a criminal defense lawyer and professor."

"And why? Because they can't contest the facts," he said.

While not naming him directly, Schiff's remarks were an oblique reference to Harvard Law emeritus professor Alan Dershowitz. Dershowitz, whose high-profile clients have included O.J. Simpson, has said he will deliver arguments on the constitutionality of impeachment.

Schiff made a similar remark during the debate on Senate trial rules on Tuesday, when he did name Dershowitz in slamming the Trump legal team's stance.

"They had to go outside the realm of constitutional lawyers and scholars to a criminal defense lawyer to make that argument because no reputable constitutional law expert would do that," Schiff said then.

Dershowitz has come under fire in recent days over comments he made about the impeachment of President Bill Clinton, during which he said there did not need to be criminal conduct in order for a president to be impeached.

He now says there must be a "criminal-like violation" for impeachment to take place. "I am much more correct right now, having done more research," Dershowitz told CNN's Anderson Cooper on Monday. "I didn't do the research back then. I wasn't wrong. I am just far more correct now than I was then."

Dershowitz is one of several outside attorneys the president has tapped to defend him in the impeachment trial. White House counsel Pat Cipollone and Trump personal lawyer Jay Sekulow have taken the lead, and are joined by others such as former independent counsel Ken Starr and Starr's successor, Robert Ray.

Trump's legal team has argued in filings ahead of the impeachment trial that the president cannot be impeached for abuse of power, because there is no underlying crime.

Turley, the legal expert referenced by Schiff on Wednesday, was the sole GOP witness who appeared before the House Judiciary Committee during a hearing last month on the constitutional basis for impeachment. He argued then that the House was moving too quickly in the impeachment inquiry to press forward with articles of impeachment.

Turley, a George Washington University law professor, reiterated that point in a piece for The Washington Post Tuesday. But he raised issues with Trump's legal team's argument on abuse of power, labeling it "a view that is at odds with history and the purpose of the Constitution."

"While I believe that articles of impeachment are ideally based on well-defined criminal conduct, I do not believe that the criminal code is the effective limit or scope of possible impeachable offenses," Turley wrote. "If some of the president's critics are adopting a far too broad understanding of impeachable offenses, the White House is adopting a far too narrow one."

Read more:

No Ordinary Trial: The Case on Trump's Impeachment Gets Underway

Roberts Admonishes Impeachment Lawyers to 'Remember Where They Are'

'Material Witness': House Picks Fight With Pat Cipollone as Trump Goes on Trial

'I Have a More Sophisticated Basis for My Argument': Dershowitz, Backing Trump, Denies Flip-Flop on Impeachment