Mr Clinton's image, already tarnished by revelations of his sexual habits and alleged cover-up efforts, will be ripped to shreds as Americans see a usually calm and avuncular man quarrelling with his accusers, losing his temper and avoiding difficult questions.
The tape is a record of Mr Clinton's testimony to Kenneth Starr's inquiry into his sexual misdoings and attempts to cover them up. It shows the President as evasive and angry, far from his current public persona of a man who is contrite about his past behaviour. He wavers over definitions of sexual acts, refuses to answer some questions, argues about others, which he says criminalise his private life, and is generally unhelpful.
He was, of course, conducting his defence in a legal context, but the appearance will do him grave damage. It will harm his image, and most importantly, confirm the view that he sought to avoid the truth.
The tape runs for four hours, covering the afternoon of 17 August which the President spent in the White House Map Room under questioning from Mr Starr's assistants. The President had spent the morning being briefed on planned missile strikes against Sudan and Afghanistan, a bizarre juxtaposition that cannot have helped his temper. He was also arguing with aides about the terms of a televised broadcast that evening to the American people on his misdeeds, a broadcast which at the time was deemed by many to be insufficiently contrite, and which indeed criticised Mr Starr.
The cable networks - CNN, MSNBC and Fox News Channel - plan to air all four hours, virtually unabridged. They were scrambling to decide on the precise arrangements yesterday. In particular, there may be scenes or words that they do not wish to air, and some may use a tape delay. The main networks - CBS, ABC and NBC - will show excerpts, but probably not all of the tapes. All are aware that the timing - the tapes will probably be released this morning - means that they will have little time to review all four hours before they air it.
The Judiciary Committee of the House of Representatives met yesterday to approve the release of the tape. There was strong resistance from the panel's Democrats, but they are in a minority. The Republicans say it is important people see how the President tried to evade questions, as part of an effort to show he is guilty of perjury.
It is not just the videotape that is at issue: there are 2,500 pages of appendices to the report as well as 17 boxes of other material - transcripts, videos and audiotapes. Some of it is dynamite, containing highly personal revelations by witnesses, and some of it may never be released.
The committee started off by claiming that it would be a bipartisan effort to decide whether to launch impeachment proceedings: that has very quickly come to grief, and things are now little better than a bar-room brawl. "They talk about wanting bipartisan co-operation but so far they have just been rolling over us," said Maxine Waters, a Democrat on the committee. "They have the votes and they can do that."
The possible consequences of recent events led the Congress to forge a unique agreement yesterday that neither party would use smears against the other in forthcoming elections. It followed revelations that Henry Hyde, the Republican chairman of the Judiciary Committee, had been unfaithful to his wife more than 30 years ago - raising fears in both parties that the Clinton revelations would trip off a "sexual Armageddon", where every politician's dirty laundry was washed in public.
John Linder, chairman of the Republican campaign committee, and Martin Frost, his Democratic counterpart, agreed that neither organisation would fund candidates who use personal attacks.
"Initiating a personal attack on anybody running for office is simply off limits," said Mr Linder. "We are soon going to have no one of any stature willing to put themselves through this wringer, and it is sad for America."