Clinton accused: All the presidents' women: How the most powerful men on earth had feet of clay

If Bill Clinton has had difficulty keeping his hands off a pretty girl, he is hardly the first American president to have had this problem: John Kennedy blazed that trail for him extravagantly, and even Franklin Roosevelt had his sentimental adventures. If, as is alleged, Bill Clinton has committed adultery inside the sacred precincts of the White House, even in that he is not alone. Warren Harding made love to his girlfriend in a coat-cupboard there because he was afraid of being surprised by his wife

Bill Clinton is in danger of being remembered as more like Harding than Kennedy. Worse, he looks like kicking the office of the presidency back down the slope up which Ronald Reagan painfully dragged it. For if the presidency is expected to be the key and master office of American government, in practice, for more than 40 years, it has more often than not been almost impotent.

Mr Clinton quite probably faces a media feeding frenzy that will make the OJ Simpson trial look quaint. The distinguishing characteristics of the presidential penis will be mercilessly discussed. Legislatively, President Clinton's administration is already to all intents dead in the water. Any hope of future achievements is barred by the contemptuous obduracy of the Gingrich conservatives in Congress. Indeed, some Washingtonians are afraid that the President may be tempted to ease the pressure by picking a quarrel with Saddam Hussein or some other whipping boy.

When John Kennedy gave his great inaugural address in a snowstorm, 37 years ago this month, the presidency seemed destined to fulfil great expectations. By 1974, when Richard Nixon fell, it was dysfunctional and discredited. Kennedy was assassinated, Johnson forced to abdicate, Nixon driven to resign to avoid almost certain impeachment. Ford was inept, Carter lucky.

True, in a burst of creative political action which took every advantage of Kennedy's death, Lyndon Johnson pushed through an impressive slate of reform legislation, including the Civil Rights Act of 1964, but these triumphs were against the grain of a political mood that was already suspicious of "big government".

Again, in the summer of 1981, Ronald Reagan enjoyed a honeymoon with Congress, but the relationship was short-lived.

Even by Kennedy's time, the presidency had fallen victim to serious, long-term problems. Their nature was concealed to some extent by the power given to the chief executive by the Cold War and the rise of the national- security state. But their origins go back to the Constitution itself, with its design of separating the powers of executive and legislature, and then "checking" and "balancing" those powers. Only in rare conjunctures can a president work effectively with Congress to address national needs.

Franklin Roosevelt, faced with near-breakdown of the American economy, was able to give some effect to his popular mandate through four relationships: with Congress, through a Democratic majority; with the Democratic party; with the bureaucracy of the "permanent government"; and with the media, especially radio. Each of those connecting rods has broken in the hands of recent presidents. The Congress is firmly controlled by conservative Republicans, the White House by a Democrat who seems, to them at least, a liberal. Party ideology may still count for something, party organisation is almost non-existent. The bureaucracy is demoralised. And the media lie largely beyond the President's influence.

If Bill Clinton is impeached, it will not be because of sexual acts, but because of the way he may have sought to interfere with legal process to cover them up. If he is discredited, it will not be because of the women he has gone to bed with, but because of the suspicion that he has used his authority as governor and then as president to harass them into doing so.

He may be able to hold off the pursuit. He is an able politician, and a man with once high ideals. But it is already plain that he has not been able to escape from the trap laid by the American system itself. The Founders were so intent on checking the power of the executive that they made the government impotent in all circumstances except the most obvious emergencies. The irony is that Bill Clinton has presided over a remarkable period of economic growth and revival. But he is now in danger of learning in the most humiliating way that ... it isn't just the economy, stupid.

Godfrey Hodgson is a Fellow of Green College, Oxford. One of his six books about American politics is "All Things to All Men: the False Promise of the Modern American Presidency" (1980).