Rupert Cornwell: The winning ticket in the sweepstake of political life

'If you get elected as vice-president, you've a 50 per cent chance of winning the top job'

If you wonder why Dick Cheney and Joseph Lieberman these days grin as though they have drawn the best tickets in the great sweepstakes of American political life, the answer is simple. They have.

If you wonder why Dick Cheney and Joseph Lieberman these days grin as though they have drawn the best tickets in the great sweepstakes of American political life, the answer is simple. They have.

Forget the jokes about the office they are competing for, and study the statistics. A dozen men have been vice-president of the United States since Harry Truman was elected in 1944. Of them, five have become president and a sixth, Al Gore, may join them next January. Two others have won their party's presidential nomination but lost.

In other words, get elected vice-president and you've a 50 per cent chance of winning the top job one day. And not just because of resignation or assassination, though both have occurred in the last 40 years. The greatest advantage of being vice-president of the United States is that, if you behave, you will inherit the party machine.

Once of course there was indeed a heavy price to pay, only underscored by the invariable pledge of an incoming president to run a more collegiate administration, which would make full use of his deputy's talents. The gentleman in question would duly be given an array of committees and task forces to preside, plus an ex officio seat on the national security council, and the promise of a weekly lunch with the boss.

But that, until recently, was as far as it went. A vice-president's value consisted of his short-term electoral dowry to the ticket (in Lyndon Johnson's case in 1960, credibility for John Kennedy in the South and victory in his crucial home state of Texas). Once in office however, his only duty laid down by the constitution is to preside over the Senate and cast the deciding vote in the case of a tie. His importance was simply that he existed, a back-up president, just in case. The aphorism of George Bush Snr, eight years under Ronald Reagan, summed it up perfectly: "90 per cent of life is showing up."

But for larger vice-presidential egos, mere "showing up" would never suffice. After a career as the most domineering and hands-on Senate leader of his era, Lyndon Johnson, "LBJ", loathed the job - he was excluded from the Kennedy circle and bundled on to Air Force Two to wave the flag in foreign countries he had barely heard of, primarily to keep him out of the hair of the Kennedy brothers.

And like many fathers brutalised by their parents during childhood, Johnson visited similar cruelty upon his own vice-president, the inexhaustible Hubert Humphrey, by mixing neglect with demands for an unquestioning loyalty that would destroy Humphrey's own bid for the White House in 1968.

No one was more brutally honest than Dwight Eisenhower, after Richard Nixon once claimed that eight years as Eisenhower's vice-president had given him unique qualifications to be president. Asked by the press what these qualifications might be, the good general replied, "Give me a week and I'll think of something."

John Nance Garner, a Texan who held the job for Franklin D Roosevelt's first two terms in the Thirties, famously remarked that the vice-presidency was not worth "a pitcher of warm spit". Sixty years on, this no longer holds. In an age when the workload of the president - simultaneously head of state and head of government of a country whose power is unique in history - grows ever huger, the vice-presidency matters as never before.

In fact, the George Bush, who so faithfully showed up, will go down as the first modern vice-president; careful never to up-stage the boss, but exerting backstage influence and with enough foreign policy experience to negotiate on behalf of the administration in his own right.

Under Bill Clinton, Al Gore has carried the process further. Another young, moderate southerner, from a neighbouring state, he brought no geographic or ideological dowry. His value lay in his expertise in foreign and security policy, where Clinton was seen as weak. So well did the two get on that Clinton allowed Gore to become arguably the most powerful vice-president in US history. In the process, a bargain was struck. In return for Gore's loyalty, tested to the limit by scandal, Clinton would do everything he could to ensure that Gore was his successor.

And come November, it may be pay-off day. In which case, Joe Lieberman will be the next to savour the curious statistics of advancement that go with this once-reviled job. But it was ever thus. "My country has in its wisdom contrived the most insignificant office that the invention of man ever conceived," the first vice-president, John Adams, wrote to his wife Abigail in December 1793. "And as I can do neither good nor evil, I must be borne away by others and meet the common fate." And what happened? You guessed. In 1797 Adams succeeded George Washington as president. So much for common fate.