The members of Trump's impeachment defense team

Prominent attorney Alan Dershowitz and two former independent counsels, Ken Starr and Robert Ray, will be among those defending President Donald Trump when his impeachment trial begins in the Senate in earnest on Tuesday.

Here is some background on Trump's defense team, as well as two lawmakers who may join it.

Pat Cipollone

The White House counsel, 53, will lead Trump's defense. He has aggressively defended the president during the impeachment inquiry, and refused to produce documents and witnesses requested by Congress.

Before he joined the administration in 2018, Cipollone was a name partner at a small Washington litigation firm.

He is also a former partner at a major law firm, and served as general counsel for the Knights of Columbus, a Catholic fraternal organization. He also has been involved with the conservative Federalist Society, an influential legal group.

Jay Sekulow

Sekulow, 63, will help lead Trump's defense. He is a private attorney for Trump, who was initially hired during Special Counsel Robert Mueller's investigation into Russian meddling in the 2016 election. He also has helped manage other cases against Trump, including in the fight over disclosure of his tax returns.

Sekulow is host of a daily radio talk show and chief counsel for the American Center for Law and Justice, a nonprofit that advocates for religious freedoms and is known for supporting Christian causes. He has argued a dozen times before the US Supreme Court.

Alan Dershowitz

Dershowitz, 81, has been a well-known figure in US legal circles for decades. The Harvard Law School professor successfully defended former National Football League star OJ Simpson on charges of murdering his wife and a friend of hers in 1995 and represented financier Jeffrey Epstein against sex crime charges, for which he pleaded guilty in 2008.

Dershowitz says he voted for Trump's Democratic presidential rival Hillary Clinton in 2016, but has since emerged as a high-profile defender of Trump on cable television and has written a book opposing his impeachment.

At the Senate trial, Dershowitz will present constitutional arguments against impeachment and removal from office, according to Trump's legal team.

"He is participating in this impeachment trial to defend the integrity of the Constitution and to prevent the creation of a dangerous constitutional precedent," the legal team said in a prepared statement.

Kenneth Starr

Starr, 73, is the former independent counsel whose investigation paved the way for the impeachment of former President Bill Clinton, a Democrat, in 1998.

A former appeals court judge, Starr was appointed independent counsel in the mid-1990s to investigate a real estate deal and other matters, but his probe widened to include Clinton's sexual relationship with White House intern Monica Lewinsky. The House voted to impeach Clinton but the Senate acquitted him.

Starr was president of Baylor University in Texas, the world's largest Baptist college, but resigned in 2016 amid criticism of the schools' handling of sexual assault allegations.