Ms Tripp is the woman who used a concealed tape-recorder to document the confessions and complaints of 24-year-old Monica Lewinsky about her relationship with the President. She handed the tapes to a prosecutor, Kenneth Starr, who was already investigating other allegations against Mr Clinton, and she then agreed to be "wired" by the FBI to continue her sleuthing on their behalf.
With neither Ms Lewinsky nor Mr Clinton prepared to retract their sworn denials of an affair, Ms Tripp is Kenneth Starr's best hope of making his case. He wants to establish which version of Monica's story is true: the version on the tapes - with its salacious allusions to sex with the President - or her denial. And if he can prove that she (and therefore he) lied, he then wants to establish whether Mr Clinton tried - through threats or inducements - to buy her silence.
Legally, such allegations could support charges of perjury and obstruction of justice. Brought against a president, such charges could justify impeachment.
Until recently, the case seemed clear-cut, if unresolved. One way or another, Ms Lewinsky was lying. If she was lying on the tapes, she was a scheming fantasist. If she lied under oath, she was a perjurer, and so was Mr Clinton. He was also an adulterer and probably, given that Ms Lewinsky was a trainee at the White House when the alleged affair began in November 1995, a sexual harasser as well.
As the weeks have passed, however, what went on at the White House between Bill Clinton and Monica Lewinsky (and no one has denied that something did) has begun to look both more complicated and perhaps more simple. And as more small pieces of evidence are reeled in by reporters desperate for new information and leaked by advocates keen to protect friends and patrons, a scenario is starting to take shape in which most of the information made public so far can be reconciled, however contradictory much of it seems.
The tale that looks likely to emerge is as old as the world and as basic, but less malign than suspected, and more confused than criminal.
Here is an older, immensely powerful man lionised by a young and sexually enterprising woman. He has a past, and a weakness for women. He also has a wife and daughter he cares for, a job that demands a certain image, and a private promise about how to conduct himself as President. She has healthy appetites and a future, and she believes, in the American way, that anything is possible.
That there was some sort of relationship between them seems incontrovertible. Photographs of Monica Lewinsky in Mr Clinton's presence show her wide- eyed and ecstatic, and corroborate reports that she contrived to be near him. When asked about his relations with her, Mr Clinton has looked rueful and, initially, embarrassed.
No one contests reports that Ms Lewinsky was transferred to the Pentagon because she sought out the President, and that her behaviour was judged inappropriate. Details of White House entry logs, leaked to the New York Times, show Ms Lewinsky making dozens of visits to the presidential wing even after her transfer.
Yet for Mr Clinton to go on the record to deny an affair, as he has done three times - once under oath in the Paula Jones sexual harassment investigation, once in a television interview and once in a belligerent televised statement where he jabbed the air with his finger for emphasis - would be risky in the extreme unless he was confident of his innocence.
So far, the fragmentary and disparate evidence points in one direction. Lewinsky was lonely, bold and single-minded. Clinton was lonely and weak. She insinuated herself into his presence. They fooled around, but he set limits which, unless she is lying, he kept to. She grew frustrated; he became worried. The late-night visits when Hillary was out of town, the phone calls (phone sex, according to the tapes), the presents, all added up to an affair which, by his definition, did not exist.
Other women of Mr Clinton's acquaintance have made complaints similar to those Ms Lewinsky voiced to her confidants: he courted them, fooled around, perhaps solicited oral sex, but rarely indulged himself further. The political cost of succumbing to temptation was too great.
Mr Clinton may have a past, but whether he carried it into the white House is another matter. A former White House employee, Gary Aldrich, claimed in a book that the President would escape incognito to a city hotel to meet a mistress during his first term, but he subsequently withdrew the allegation. As Ms Lewinsky's transfer attests, White House aides made efforts to remove temptation from his path.
But they did not fully succeed. Some reports suggest that Ms Betty Currie, Mr Clinton's private secretary, signed Ms Lewinsky in to the presidential wing of an evening. Others say that Ms Currie was absent on the days Ms Lewinsky was admitted, but her name was used on the log. What seems certain is that when the relationship ended, Ms Currie was the go-between, recovering presents and perhaps other evidence at the behest of Monica and - by then - her desperately worried mother.
Some of the pieces were filled in, perhaps unwittingly, by Dale Young, friend of the Lewinsky family and confidant to Monica, who testified to the investigation last week - then told Newsweek magazine what she had said. Her version has a ring of truth and spontaneity lacking from the heavily lawyered statements produced by others, and suggests an affair that never went beyond "a sort of foreplay" and was finally broken off by Mr Clinton in words that, even at third hand, have a perverse plausibility. According to Dale Young, quoting Ms Lewinsky, Mr Clinton "wanted Chelsea, his daughter, to be proud of him and he wanted to be a good husband and he didn't want to do anything like this any more".
Of course, there is room for scepticism about the truthfulness and motives of almost everyone involved. Is Linda Tripp an icon of rectitude, whose only thought in 20 hours of secret tape-recording was for the integrity of the US presidency - or did she have it in for the President as a political, personal and moral adversary? Was Luciane Goldberg, the New York literary agent who is believed to have leaked the first excerpted transcripts of the tapes, just trying to protect Ms Tripp's good name, or was she intent on besmirching the President, and leaked only the most damaging sections of the tapes to that end?
Was a second tranche of tapes, leaked to US News and World Report 10 days ago, intended to present Monica as a love-struck innocent and so protect Mr Clinton? And what does Monica mean by "sex"? (We know what Mr Clinton denies, as the question was posed in great detail when he was questioned by lawyers in the Paula Jones sexual harassment suit - and it includes oral sex and touching of genitalia.)
What emerges is a sordid tale of infatuation and embitterment on Ms Lewinsky's part, but an embitterment she has been reluctant to use against the President - according to some reports, because she still "adores" him. All of which might have been successfully controlled and concealed, had Ms Lewinsky not been summoned to testify in the Paula Jones case. Ms Jones's lawyers were gathering evidence about Mr Clinton's relations with women, and called - among half a dozen others - Ms Lewinsky.
At this point, a degree of panic seems to have gripped the White House, a fear that she might tell all under oath - or perhaps more than all, out of bitterness or over-eagerness to please. Word would then inevitably get back to Hillary and Chelsea, and to the press. There followed a desperate scramble to get her a job, out of government and out of town; perhaps to teach her and others (Linda Tripp, Betty Currie) some legal lines to keep the President out of trouble.
These are the actions - the job search, the legal instructions - that could be interpreted as attempts to pervert the course of justice. If the President has lied about the nature of the affair, that is what they are. But if his chief worry was that a possibly exaggerated version of his indiscretion would get back to his wife and daughter, something different is going on, something where the criminal law has no place.
In that case, when the truth is out, the President may look foolish and weak in one area of his life, but not nearly as foolish or weak as he would have looked had the affair progressed, and not - quite - a liar. He was just someone trying to keep his family together, who happened also to be President of the United States.Reuse content