The impeachment trial of President Clinton will formally open today in the US Senate when the 100 members are sworn in as jurors.
It will be the first such trial of a US president since that of President Andrew Johnson in 1868. Arrangements have been made for special passes for members of the public who wish to attend.
A CBS News poll showed that six of 10 Americans say they think a full trial of President Clinton is not necessary. Almost the same number think a full trial would have a serious negative impact on the country.
Behind the scenes senior Republican and Democratic senators are trying to agree on a format which would prevent the trial going on for months and paralysing the work of Congress. A compromise plan to have a trial without calling witnesses has been rejected by the conservative Republicans.
It now looks certain that witnesses will be called, thus prolonging the trial. President Clinton is due to give his State of the Union address to Congress on January 19th, and it had been hoped to have the trial concluded by then.
The proceedings will open today when Republican prosecutors or "managers" from the House of Representatives will cross the Capitol building to read the two articles of impeachment. The articles charge President Clinton with perjury and obstructing justice arising out of his affair with Ms Monica Lewinsky.
If two-thirds of the 100 senators find Mr Clinton guilty of one or more of the charges, he will be dismissed from office. In 1868 President Johnson was saved from this fate by just one vote. In the present Senate there are 55 Republicans and 45 Democrats.
After the reading of the articles of impeachment, the Senate will summon the Chief Justice of the Supreme Court, Judge William Rehnquist, to preside.
He will swear in the 100 senators as jurors. They will swear to act impartially, but inevitably they will be influenced by their views as Republicans and Democrats.
After this formal opening, it is still not clear when the trial proper will get under way. It was hoped to start next Monday with a presentation by the prosecuting team of the charges against the President. But now it looks as if this will be put back until later in the week.
The Republican majority leader, Senator Trent Lott, said it was not possible to say how long the trial would last while there was still no agreement between the two parties on how it will proceed. Senator Lott said that the trial would not tie up the Senate completely and a "dual track" process would be possible, allowing legislative work to continue.
The Democratic minority leader, Senator Tom Daschle, made it clear that the Democrats are opposed to the idea of calling witnesses. The White House has been expressing frustration at the lack of agreement on the format for the trial.
Meanwhile in the House of Representatives, the new Republican Speaker, Mr Dennis Hastert, was elected to replace Mr Newt Gingrich, who had served as speaker since 1994.