• Dershowitz says the allegations against Trump don't meet constitutional standards
  • The addition of Dershowitz and Starr brings the number of attorneys defending Trump at his Senate trial to six
  • Starr prosecuted former President Bill Clinton for lying about his relationship with Monica Lewinsky

Attorneys Alan Dershowitz and Kenneth Starr Friday were added to President Trump’s legal team, joining White House counsel Pat Cipollone and Trump personal lawyer Jay Sekulow, to defend him against articles of impeachment accusing him of abuse of power and obstructing Congress.

Trump’s impeachment trial in the Senate gets underway in earnest on Tuesday.

Dershowitz, a Harvard law professor emeritus -- who gained fame in the 1970s for his involvement in the Chicago Seven trial and went on to represent such high-profile clients as O.J. Simpson, kidnapped heiress Patty Hearst and Claus von Bulow -- has said the impeachment articles approved against Trump failed to meet constitutional standards.

Starr, who served as a federal appellate judge and solicitor general, is best known for his role as independent counsel investigating members of the Clinton administration. He was first appointed to investigate the suicide of deputy White House counsel Vince Foster and the Clintons’ Whitewater real estate investments. He eventually accused former President Bill Clinton of lying in a deposition over his sexual involvement with White House intern Monica Lewinsky. The perjury allegations resulted in Clinton’s impeachment and the suspension of his law license.

Also on Trump’s team are Jane Raskin, who participated in the investigation into Russian election interference, and Robert Ray, who was part of Starr’s Whitewater investigation.

Dershowitz confirmed his involvement in the impeachment trial on Twitter. He said he will present the constitutional arguments against impeachment and removal from office.

“While Professor Dershowitz is nonpartisan 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,” Dershowitz tweeted. “He is participating in this impeachment trial to defend the integrity of the Constitution and to prevent the creation of a dangerous constitutional precedent.”

Former House Speaker Newt Gingrich chortled over the announcement, saying Reps. Adam Schiff and Jerrold Nadler, who will take the lead prosecuting the House’s case against Trump, are no match for Dershowitz and Starr.

The Senate heard the reading of two articles of impeachment against Trump Thursday, then swore in U.S. Supreme Court Chief Justice John Roberts who pledged to do “impartial justice” in presiding over the trial. Roberts then swore in the senators as jurors in the case.

Trump is accused of trying to pressure Ukraine to announce an investigation into former Vice President Joe Biden, the leading candidate for the Democratic presidential nomination, in exchange for $391 million in military aid and then blocking Congress from investigating his actions.

The Government Accountability Office Thursday issued a legal opinion saying the administration broke federal law covering disbursement of funds approved by Congress by delaying the aid to Ukraine.

Trump is expected to be acquitted by the Republican-controlled Senate. It is still unclear whether any witnesses will be called.