Alan Dershowitz, former Harvard Law School professor and controversial defense attorney, made his debut in the Senate impeachment trial of President Donald Trump on Monday with a deep history lesson and argument that the president cannot be convicted without an actual criminal offense.

Trump’s defense team teased Dershowitz’s arguments more than once throughout the day, like the evening news promotes its big story. And it was not an accident that the star consultant on the Trump defense team landed in primetime.

Dershowitz is a proud contrarian and highlighted almost immediately that he did not vote for Trump. He is against the impeachment of the president based on the charges put forth by the House articles and arguments that he says do not rise to a criminal offense and therefore are not impeachable.

“I would be making these very same constitutional arguments had Hillary Clinton, for whom I voted, been elected and had a Republican House voted to impeach her on these unconstitutional grounds. I am here today, because I love my country and our Constitution,” he said.

Dershowitz was the first Trump defense counsel to address the draft of former National Security Adviser John Bolton’s book reported by The New York Times on Sunday that says Trump directed Bolton to pause military aid to Ukraine until Kyiv investigated Trump’s rivals.

“Nothing in the Bolton revelations, even if true, would rise to the level of an abuse of power or an impeachable offense,” he said.

Dershowitz’s role was to put the charges against Trump in a constitutional context, working his way through history beginning with the Constitutional Convention in Philadelphia up to the present.

He said he “abhorred” former President Richard Nixon, “whose impeachment I personally favored,” and said he opposed the impeachment of Bill Clinton.

“I stand against the application and misapplication of the constitutional criteria in every case, and against any president without regard to whether I support his or her policies,” Dershowitz told the senators.

Dershowitz has gained notoriety by representing high-profile clients including O.J. Simpson, Mike Tyson, newspaper heiress Patty Hearst and most recently financier and convicted sex offender Jeffrey Epstein.

‘Best friend’

Trump’s lawyers on Monday doubled down on their defense of the impeached president, arguing their client did nothing wrong and raising similar themes the president and his allies have stressed for months. 

Throughout the fifth day of the Senate’s impeachment trial, Trump’s legal team argued the president — who Democrats say withheld millions in military aid intended for Ukraine in exchange for a political favor — has worked to defend Ukraine, downplayed the roles of Trump’s associates in the alleged scheme and attacked former Vice President Joe Biden and his family.

Jay Sekulow, one of Trump’s lawyers, told the Senate that Trump has been a “best friend” to Ukraine.

Sekulow argued that because Trump approved the delivery of lethal military weapons to Ukraine, which has been fighting Russia-backed separatists, Trump has proven to be a more reliable patron to the U.S. ally than his predecessor.

Barack Obama blocked the United States from arming Ukrainian forces with lethal weapons after Russia invaded and annexed Ukrainian territory in 2014. But the Obama administration did provide the country with military equipment, such as vehicles, training and other support.

“These are the facts,” Sekulow told the Senate of Trump’s support of Ukraine.

But at the center of the impeachment trial is Trump’s decision to delay the delivery of nearly $400 million to Ukraine over the summer.

Democrats contend that Trump withheld the aid as leverage to pressure Kyiv to announce an investigation into Biden’s son Hunter, who sat on the board of a Ukrainian gas company while his father was vice president and involved in U.S. foreign policy decisions in that country.

No entity in either the United States or Ukraine has found any wrongdoing by either of the Bidens, a point Biden’s campaign stressed Monday.

That proposed investigation, Democrats argue, was intended to bludgeon Biden’s chances at the nomination and the presidency. The aid was eventually delivered to Ukraine, though Democrats contend it was only dispersed because Trump’s scheme was exposed.

[House Democrats are making McConnell — not Trump — their new boogeyman]

Throughout the day, Trump’s team worked to convince the Senate that Trump’s desired investigation into the Bidens was a legitimate endeavor and not one intended to give Trump an electoral edge.

Trump’s defense team, like House Republicans during the impeachment inquiry, argued that Trump sought the investigation to uncover corruption. The team made the case that Hunter, who had no prior experience in energy or Ukraine, secured his lucrative sinecure at gas company Burisma because he was the vice president’s son.

Former Florida Attorney General and Trump lawyer Pam Bondi detailed how Burisma and the oligarch who ran it avoided lawsuits while Hunter sat on its board.

Meanwhile, Trump’s attorneys argued, Joe Biden was involved in U.S.-Ukrainian foreign policy and pressured Ukraine to fire its prosecutor general while Burisma avoided those lawsuits during Hunter’s tenure.

Trump’s defense team also worked to diminish the role of Rudy Giuliani, the former mayor of New York and Trump’s personal lawyer, in Trump’s alleged scheme.

Trump attorney Jane Raskin called Giuliani “a minor player,” and a “shiny object.”

That statement contrasts with the U.S. ambassador to the European Union’s testimony before the House late last year that Giuliani was among Trump’s closest confidants with respect to Ukraine.

“We worked with Mr. Giuliani because the president directed us to do so,” Gordon Sondland told the House Intelligence Committee. “Until Rudy was satisfied, the president wasn’t going to change his mind.”

Monday’s arguments occurred amid chatter that there could be enough votes to subpoena Bolton to testify before the Senate.

Following the reports that Bolton’s coming memoir, Utah Republican Mitt Romney and Maine Republican Susan Collins indicated they would like to hear from Bolton directly.

The Senate resolution governing the impeachment trial allows the Senate to vote on whether to hear from witnesses. That vote will likely take place  Friday.