WASHINGTON (AllPolitics) -- In moving forward with President Bill Clinton's impeachment trial, the Senate agreed January 27 to allow depositions of three witnesses involved in the sex-and-perjury scandal.

They are:

Monica Lewinsky

A 25-year-old former White House intern, Lewinsky is the woman at the heart of the scandal. Lewinsky came to the White House in June 1995 and later became a salaried employee in the White House Office of Legislative Affairs. She says her trysts with Clinton began in late 1995 during the government shutdown. She moved to the Defense Department in April 1996 and left the Pentagon, apparently on good terms, in December 1997.

Vernon Jordan

An influential Washington lawyer and close advisor to Clinton, Jordan chaired the president's transition team in 1992. The two are frequent golfing partners. Jordan sits on several major corporate boards and referred Lewinsky to two companies for possible employment. He helped Lewinsky find a Washington lawyer to help with her Paula Jones case affidavit, in which she denied having a sexual relationship with the president. Jordan said she told him the same thing. At issue is Jordan's job assistance to Lewinsky.

Sidney Blumenthal

A White House communications aide and former reporter, Blumenthal joined the administration to help with speech writing and communications strategy for Clinton's second term. At issue is what Clinton told Blumenthal immediately after allegations about the Clinton-Lewinsky relationship became public in January 1998.