The room has been renovated, the locks changed, and armed Capitol policemen have been standing guard around the clock to ensure no one enters it. Although the room, H2-186 in the Gerald R Ford building of the United States House of Representatives, has been transformed into Washington's version of Fort Knox, what it really represents is a political Pandora's Box. Opening the door and examining the contents has become the most important task to which Congress has been entrusted for many years; but where the discovery will lead them is something no one in America can predict. The room, of course, contains 18 boxes (plus another 18 in duplicate), crammed with legal analyses and evidence which independent prosecutor Kenneth Starr, after four years of investigation, believes to be the basis to have President Bill Clinton forcibly removed from office. All the suggestive and tawdry details of the past year's revelations of the Clinton-Monica Lewinsky soap opera have been reduced to legalistic black-and-white: transcripts of the infamous taped phone calls between Ms Lewinsky and her fair-weather friend Linda Tripp; DNA analysis of stains on Ms Lewinsky's legendary Gap dress; grand jury testimony from an honour roll of Clinton staffers and associates; and Mr Starr's own summary of why Mr Clinton should, for the first time in American history, be successfully impeached. Public revelation of some of the graphic details of the dalliances in the Oval Office study might, to many people in Mr Clinton's position, be so embarrassing as to be punishment in itself; and by now, if Congress' plans to release the 445-page report on the Internet have gone ahead as planned, every computer user in the world will already have all the dirt within modem's reach. Until Mr Starr's men delivered the two van-loads of documents to the Capitol steps on Wednesday, the true significance of this nine months of madness had not truly sunk in. The president's high poll ratings, and the fear of Congress of wading in too deep into the impeachment process, had made it seem highly unlikely the Lewinsky saga would ever lead to much of import. But now Mr Starr has done his duty (or at least part of it - he seems to have strayed well off the path of his initial probe into the Whitewater matter), the die has been cast. The founding fathers gave Congress one of the most important roles in maintaining the republic's democratic balance and preventing the abuse of executive power: the capacity to impeach the president. Mr Starr's documents mean it must now grasp the mantle with all the gravitas in its power. What a difference three weeks has made to the mood not only on Capitol Hill, but in the White House. When President Clinton agreed to go before Mr Starr's grand jury on August 17, he did so secure in the knowledge - or so his lawyers and pollsters thought - he could crawl his way out of the political hole with a half-hearted, lawyerly admission of what he had done. But the misguided defiance of his live televised speech, far from putting the country's mind at rest, set in motion the wheels of outrage that now have him staring into the political abyss. Mr Clinton miscalculated that the cabinet colleagues and congressional Democrats he had been lying to for months would continue to hold the fort once he came clean; having been used, all through his career, to seeing friends and colleagues as political cannon-fodder, there was no reason to assume this time would be any different. But as, one by one, close Democratic supporters such as senators Joseph Liebermann and Daniel Moynihan have gone public with their sense of anger and betrayal, Mr Clinton's August 17 gamble has proved to be the worst mistake of his political life. Barely a day now goes by without Mr Clinton digging deeper into the public's well of sympathy with another apology. But it is too late - for what happens now is entirely out of his control. Mr Starr has cranked the gears on the wheels of the impeachment process, and whether the president serves out the remainder of his term resides wholly in the hands of the legislature. House Speaker Newt Gingrich and his Democratic counterpart, Richard Gephardt, said this week that short of going to war, there is no task more onerous than the one now entrusted to Congress. And what makes it all the more arduous is the lack of historical guidelines and precedents to steady its hand. Under Article II, Section 4 of the Constitution, the president and other senior US officials (including federal judges) 'shall be removed from office on impeachment for, and conviction of, treason, bribery, or other high crimes of misdemeanours'. The process itself is not in contention. What happens now is that the House Judiciary Committee will hold hearings - which could conceivably last for weeks or months - to examine Mr Starr's evidence and decide whether to recommend impeachment. If this happens, the matter is then passed to the Senate for an impeachment trial, presided over by the Chief Justice of the Supreme Court, at the conclusion of which a two-thirds majority of senators is needed to fire the president. Matters have gone as far as a Senate vote only once before - in 1868 when, after a bitter post-Civil War row with the Republican-led Congress, Democrat Andrew Johnson survived by one vote. In 1974 - the closest thing today's legislators have to anything like a precedent - the House Judiciary Committee voted three articles of impeachment against the Watergate-scarred Richard Nixon, who resigned before the matter could go to the Senate. There are two major dilemmas now facing the House: whether lying under oath about a private sexual matter (which is basically the crux of the case) constitutes the founding fathers' definition of 'high crimes and misdemeanours', and whether to view the impeachment process as a legal or a political one. If anyone knows how difficult it is to get inside the mind of the framers of the Constitution, it is Hillary Clinton. Not long before she married the young Mr Clinton, she was a junior legal counsel on the Judiciary Committee which voted to impeach Nixon. One of her tasks, tellingly, was to prepare a report analysing the historical precedents and background which might help members judge what to do with the Nixon case. The main issue at that time was deciphering what 'high crimes and misdemeanours' meant - a question which was never really answered, and which remains just as pertinent in 1998. Historical records show that in 1787, the framers, fearing that treason and bribery were not in themselves reasons enough to protect against an abusive president, debated adding a more catch-all phrase such as 'maladministration'. When that term was thought to be too vague, one of the framers, George Mason, suggested 'high crimes and misdemeanours' - a legal term taken directly from America's old enemy, the English. But for today's purposes, the phrase is still maddeningly elusive. At the very least, 'misdemeanours' meant much more 200 years ago than it does now: in today's US, the phrase is a specific legal term meaning a petty crime such as shoplifting. The effect of this confusion is that what is thought impeachable is definitely in the eye of the beholder. One famous definition came in 1970 from then-Congressman Gerald Ford - who as Nixon's vice-president would go on to benefit directly from his resignation. 'An impeachable offence is whatever a majority of the House of Representatives considers it to be at a given moment in history,' he told the House. Presidents do not have to have committed a criminal offence to be impeachable. Nixon and Johnson had not, for example, committed any crime, but were judged to be a stain on the presidency. In contrast, Mr Clinton's alleged perjury may indeed be a criminal act, but the Congress could conceivably end up concluding (particularly if they pay attention to the opinion polls) it is not enough to drive him from office. Some constitutional experts say the best definition of an impeachable president is one whose acts have made him 'unfit for office' - but who is to judge? Mr Ford's words did at least go to the heart of the impeachment issue - which is that it is inextricably entwined with the politics of the day. In 1974, Congress was controlled by a Democratic leadership opposed to Nixon and his policies, but the Judiciary Committee vote to impeach was coloured by the defections of some moderate Republicans. Today's Judiciary Committee is fiercely partisan, dominated by hardline conservative Republicans squaring off against some old-time liberals. The kind of non-partisan decorum being urged by Mr Gingrich could be hard to find unless the panel's chairman, a gentlemanly 74-year-old veteran, Henry Hyde, manages to keep control and cool tempers. Whatever the evidence, the Committee will have to keep looking over their shoulders at the voters. All are up for re-election in November, and the public does not take lightly having its right to grant four years of power to the president of its choice tampered with by members of Congress. Bernard Nussbaum, Mr Clinton's first White House general counsel, believes the Nixon precedent has made it much easier and less intimidating to go for the impeachment option. 'It's less scary,' he said. 'I think we've defined it down and it's become very dangerous now because if you can do this, it really starts changing our system. If you can say the president has brought the office into disrepute that could apply to almost any president.' One compromise measure being touted is of passing a motion of censure, or disapproval - which would have the effect of expressing discontent without the pain of impeachment. It has happened only once before, in 1834, when an unfriendly Congress censured President Andrew Jackson, who not only got a subsequent Congress to overturn it, but whose happy legacy landed him on the back of today's 20-dollar bills. Whatever Congress decides, President Clinton's own legacy is certainly tarnished beyond repair. That fact, for a man who placed so much emphasis on the reputation he would leave behind, may be all the punishment he can stand.