Yesterday's witness, the third and last, was Sidney Blumenthal, known as the White House spinmeister and a friend of Hillary Clinton. A journalist for The Washington Post and The New Yorker before joining the White House, he was expected to be questioned about a conversation in which Mr Clinton reportedly described Ms Lewinsky as a stalker who had "come on to" him.
The purpose of this line of questioning was to establish whether Mr Clinton had expected, or perhaps instructed, Mr Blumenthal to disseminate negative information about Ms Lewinsky after news of their affair broke. As Ms Lewinsky had by then been called as a witness in Paula Jones's sexual harassment suit against the President and Mr Blumenthal could expect to be a witness in the Lewinsky investigation, such a move could amount to obstructing the course of justice and tampering with witnesses.
He was questioned in the same secure committee room at the top of the Capitol where Mr Clinton's friend Vernon Jordan had been the previous day. His interrogator was James Rogan, a California Republican who was one of the most aggressive members of the House Judiciary Committee in last year's impeachment hearings.
He is one of 13 House Republicans selected to present the prosecution's case in the Senate.
Mr Jordan was questioned by the milder-mannered Asa Hutchinson, of Arkansas, and the prosecutor chosen to question Monica Lewinsky on Monday was the most homely of all, Ed Bryant, from Tennessee.
His performance was criticised yesterday by some senators who had seen the videotaped interview of Ms Lewinsky's testimony, who accused him of hesitancy and getting facts wrong.
Although prosecutors had hoped one or all their chosen witnesses would add information to earlier evidence that strengthened the case against Mr Clinton, the information seeping out of the Senate, whose members are sworn to secrecy about the testimony, indicated that only the barest details had been added.
Ms Lewinsky was said to have stuck to her original version, while impressing senators as highly credible. According to Senator Larry Craig of Idaho, a Republican, she had mixed feelings about Mr Clinton. "It's obvious this is a lady who at one point in time had very strong feelings for the President," he said.
Mr Jordan was said to have added only two details to his earlier evidence, acknowledging, for instance, specific phone calls and a breakfast with Ms Lewinsky for which the prosecutors had obtained written records. But he continued to have "forgotten" key details and specifically denied advising Ms Lewinsky to destroy draft love letters to the President.
The first clashes today are likely to centre on whether the witness testimony, which was videotaped, should be made public: Republicans tend to say that it should; Democrats not. The Senate Minority Leader, Tom Daschle, said yesterday that it should be all or nothing. "If you are going to air a deposition, you'd better air the full thing," he told reporters.
But his preference was for nothing. "The public," he said, alluding to polls, "is saying over and over ... that they want this trial to end."
The chief concern of Democrats, with the White House, is still to prevent the appearance of "live" witnesses before the Senate, though the tide appeared to be turning in their favour. While Republican House prosecutors said they would continue to press for "live" witnesses, Mr Hutchinson conceded: "I think the Senators are going to be satisfied with the videotapes. It's going to be tough to make that case."Reuse content