Senators fulfil the role of jurors. They are sworn in, and must remain silent for the duration. If witnesses are called, Senators may submit written questions.
When the subject of impeachment is the President, the Chief Justice of the Supreme Court, in this case 72-year-old William Rehnquist, presides.
The Constitution says that "no person shall be convicted without the concurrence of two-thirds of the members present" - which would be 67 of the 100 Senators - and stipulates that judgment "shall not extend further than to removal from office and disqualification to hold and enjoy any office of honour, trust or profit under the United States".
This appears to preclude the levy of a fine or imposition of a formal reprimand, as some have proposed, but there is no mention of whether a fine or reprimand (censure) could be applied in place of a trial. This could be a question for dispute at the start of proceedings.
The Constitutional provisions for impeachment conclude by saying that impeachment and removal from office does not preclude subsequent prosecution. "The party convicted shall nevertheless be liable and subject to indictment, trial, judgment and punishment, according to law." This would leave open the possibility that Mr Clinton could be prosecuted for perjury or obstruction of justice - the two charges forwarded to the Senate by the House of Representatives - once he leaves office.
That provision supports the view that there may be conduct that is impeachable but not criminal and vice versa, but there may also be conduct that is both. One suggested compromise was for Mr Clinton to accept a censure and be allowed to serve out his term, on condition that he agreed to face criminal charges afterwards. Prosecutors would have two years after Mr Clinton leaves office to bring charges.
Opinions differ about the prospects for conviction. While most believe the Senators would vote along party lines, making a two-thirds majority unlikely, a few believe they would behave more as jurors, weighing the evidence and perhaps concluding that Mr Clinton should be removed.Reuse content