"Welcome to the theatre of the absurd," the White House press secretary, Mike McCurry, greeted reporters at one of his daily briefings in the most hectic week Washington has known for a long long time.

Welcome to Monicagate.

As the Washington Times, an implacable critic of the President, exulted: "The tale of President Clinton's dalliance with a starstruck White House mail girl, though still an unproven allegation, went off like a two-ton bomb yesterday, and at sundown the White House was trembling from basement to rafters."

It was actually like that here this week. Veterans of Watergate admitted that there had never been such an atmosphere of the roof falling in as the Linda Tripp tapes of her conversations with the "star-struck" Monica Lewinsky burst on the world.

Only last Saturday the world's media gathered outside the Washington office where the President was grilled for six hours about his relationship with Paula Jones and numerous other women with whom he is alleged to have had affairs. Could anything be more awful for a president of the United States?

Well, yes. The allegation that he had sex with a 21-year-old intern in the Oval Office in between running the country and keeping the peace in the world. And, more seriously, he might have urged her to lie under oath about their affair.

Monica Lewinsky swore an affidavit that there was no sexual affair but then found out that her contradictory conversations with her co-worker and friend, Linda Tripp, had been secretly taped and handed over to the independent counsel, Kenneth Starr.

The President insisted there was "nothing improper" between them. But then we were also told that he was admitting in a deposition to Paula Jones's lawyers last week that he did have a sexual affair with Gennifer Flowers, although he denied this in 1992 on nationwide TV sitting beside his wife.

The Pope's visit to Cuba was completely overshadowed as the TV networks rushed to pull their household-name anchormen back to Washington for the big story. Even that sacred ritual, the Superbowl football playoff this weekend, was pushed aside. As the storm burst, Bill Clinton was trying to get Benjamin Netanyahu and Yasser Arafat together to prevent the Middle East peace process from blowing apart. But as the two leaders arrived in the White House one after the other, it was the Clinton Presidency which was on a short fuse.

Even the most loyal Clinton supporters were shell-shocked as new revelations and allegations tumbled out. The White House press officers grimaced as the former presidential adviser, George Stephanopoulos, mentioned the Iword, impeachment, if Clinton could not wriggle out of this one.

Dee Dee Myers, former White House press secretary for the President, warned on the Today show that "regardless of whether the allegations turn out to be true, I think this is something the President is going to have a hard time living down". She declared: "If he's not telling the truth, I think the consequences are just astronomical."

Loyalist Democrats around the country who usually dismiss the regular Clinton womanising stories as more Republican-inspired smears, gulped over this one. "If it's true, he's gone," was a widespread feeling, and the VicePresident was being suddenly looked at as President Gore long before he begins campaigning for 2000.

Republican opponents were just as stunned at the allegations but tried hard not to crow, cleverly realising that this was a time for restraint as their bete noire seemed stumbling to destruction without any help from them.

Speaker Newt Gingrich advised that "every citizen ought to slow down, relax and wait for the facts to develop".

In the White House, political aides aghast at the initial weak, legalistic responses of the President advised a much more robust defence in a special press conference before next Tuesday's State of the Union address. But the President's attorneys caled for caution, aware that there could be more unexploded mines in their client's background which he has not yet revealed.

And yet how strong is the evidence against the self-styled Comeback Kid? Some 20 hours of tapes of talk between a young, flirtatious woman with a head turned by proximity to power and an older woman who has a grudge against the Clinton White House where she once worked.

Who do you trust here? Ms Lewinsky on the tapes says at one stage that she has "lied all her life". She has also sworn on oath that "I have never had a sexual relationship with the President . . . I have the utmost respect for the President, who always behaved appropriately in my presence."

Yet on the tapes she agonises that she is going to be "screwed" over committing perjury to protect the President. He advised her to go to Vernon Jordan, the President's close confidant and adviser, regarded as one of the most powerful movers and shakers in behind-the-scenes Washington.

Mr Jordan has admitted trying to get jobs for Miss Lewinsky and introducing her to a lawyer. But he told the media: "I want to say to you absolutely and unequivocally that Ms Lewinsky told me in no uncertain terms that she did not have a sexual relationship with the President. At no time did I ever say, suggest or intimate to her that she should lie."

Mrs Tripp's past is now being combed over by the media. It now emerges that she was part of Richard Nixon's dirty-tricks campaign back in 1972 when he rubbished George McGovern. But she has also had long spells as a conscientious employee in the White House and the Pentagon.

Many Americans would like to believe that Mr Clinton is also the victim of a smear campaign by Republican opponents. But it is getting harder.