WASHINGTON (Reuters) - President Donald Trump turned to some legal heavyweights to help defend him in his Senate impeachment trial with the addition on Friday of former independent counsel Ken Starr, who paved the way for former President Bill Clinton’s 1998 impeachment, and prominent lawyer Alan Dershowitz.

The team defending the Republican president will be led by White House counsel Pat Cipollone and Trump private attorney Jay Sekulow, the White House said.

Trump adviser and former Florida attorney general Pam Bondi and former independent counsel Robert Ray will also be on the team, according to the source familiar with the team’s composition.

The White House also said Jane Raskin, one of Trump’s private lawyers, and Eric Herschmann, another former independent counsel, would be on the president’s legal team.

The trial in the Republican-led Senate formally got underway on Thursday, though it will start in earnest on Tuesday with opening statements. The trial will determine whether Trump is removed from office.

The Democratic-led House of Representatives voted on Dec. 18 to impeach Trump on two charges arising from his dealings with Ukraine - abuse of power and obstruction of Congress - after an investigation that centered on his request that Ukraine investigate political rival Joe Biden, the president’s possible Democratic opponent in the Nov. 3 election.

The Senate is expected to acquit him, as none of its 53 Republicans has voiced support for removing him, a step that requires a two-thirds majority. Trump has denied wrongdoing and has called the impeachment process a sham.

Starr is a former federal judge who held a senior Justice Department post under Republican President George H.W. Bush. Starr’s voluminous investigative report on Clinton’s sexual affair with White House intern Monica Lewinsky served as the basis for his impeachment in the House on charges of perjury and obstruction of justice. The Senate in 1999 acquitted Clinton, a Democrat. Starr had recommended impeachment on 11 grounds.

In 2016, Starr was ousted as president of Baylor University, a private Baptist institution in Texas, after an investigation by an outside law firm determined that university leaders had mishandled accusations of sexual assault by football players. Critics of Starr at the time accused him of turning a blind eye to sexual violence on his campus after pursuing Clinton for a sexual relationship.

Both Starr and Dershowitz also served as lawyers for financier and convicted sex offender Jeffrey Epstein, who was found dead in his New York jail cell last year where he was being held on new sex trafficking charges.

In 1999, Trump made unflattering comments about Starr, saying in an interview on NBC’s “Today” show after Clinton’s acquittal: “I think Ken Starr’s a lunatic.” In a 1999 interview with New York Times columnist Maureen Dowd, Trump said, “Starr’s a freak. I bet he’s got something in his closet.”

‘DREAM TEAM’

Dershowitz has been a well-known figure in U.S. legal circles for decades. He was a long-time Harvard Law School professor and was part of the so-called “Dream Team” of lawyers who won a 1995 acquittal of former National Football League star and actor O.J. Simpson on charges of murdering his wife and a friend of hers. Dershowitz’s past clients also have included boxer Mike Tyson and televangelist Jim Bakker.

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Both Starr and Dershowitz were defenders of Trump in media interviews during the impeachment process. Sources working with the Trump legal team said the president wanted Dershowitz because of his background as a constitutional scholar.

A statement provided by Dershowitz from Trump’s legal team said he will present oral arguments at the trial to address the constitutional arguments against impeachment and removal from office.

“While Professor Dershowitz is non-partisan when it comes to the constitution - he opposed the impeachment of President Bill Clinton and voted for Hillary Clinton - he believes the issues at stake go to the heart of our enduring Constitution,” the statement said.

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Ray succeeded Starr as independent counsel during the Clinton investigation. On the day before Clinton left office, Ray announced that he would not criminally prosecute him in connection with perjury and obstruction.

One person who was not added to the team that will defend Trump at the trial is his personal lawyer Rudy Giuliani, who played a key role in the Ukraine matter.

Democrat Adam Schiff heads a team of seven House members who will serve as prosecutors. Schiff, chairman of the House Intelligence Committee, is a former federal prosecutor in Los Angeles.

Still to be determined is whether the Senate will allow witness testimony and new evidence or whether senators will decide the case as Majority Leader Mitch McConnell, a Republican, has suggested using only the material amassed by House investigators.

Trump involved the national collegiate champion Louisiana State University football team in the impeachment drama during its celebratory visit to the White House.

“A lot of presidents, some good, some not so good,” Trump told the team. “But you’ve got a good one now, even though they’re trying to impeach the son of a bitch. Can you believe that?” Citing themes he has raised in his bid to win re-election on Nov. 3, Trump then touted the economy and the U.S. military, adding, “We took out those terrorists like your football team would have taken out those terrorists, right?”

A pivotal event in the Ukraine matter was Trump’s firing of Marie Yovanovitch last year as U.S. ambassador in Kiev, a move encouraged by Giuliani, who was pressing Ukraine to investigate Biden.

Secretary of State Mike Pompeo broke his silence on Friday on documents released this week that suggested that Lev Parnas, a Giuliani associate, was involved in monitoring Yovanovitch’s movements before Trump removed her, raising questions about her security.

“We will do everything we need to do to evaluate whether there was something that took place there,” Pompeo, who refused to cooperate in the House impeachment inquiry, told conservative radio host Tony Katz.

“I suspect that much of what’s been reported will ultimately prove wrong, but our obligation, my obligation as secretary of state, is to make sure that we evaluate, investigate,” Pompeo said.