The Candidate: A landslide for Kerry. But can he now unseat Bush?

If the human race as a whole, rather than 50 states plus the District of Colombia, could cast a ballot this coming November, John Kerry would surely win the presidency by a landslide.

Unfortunately for President Bush-haters around the world, only the 200 million United States citizens of voting age will have that right - and the outcome is anything but sure.

Yesterday, Mr Kerry, the Massachusetts senator, sealed the Democratic nomination after a round of primary and caucus victories, clearing the way for a decisive presidential battle. The poll in November will be a battle between two candidates who are very similar, yet very different. Both John Forbes Kerry and George Walker Bush are of an age, the former 60 the latter 57. Both are scions of north-eastern money and privilege, who went to private schools. Both attended Yale, both were members of the university's Skull and Bones club, to which dark and mysterious powers are attributed.

But, as everyone knows, one went to Vietnam and the other didn't. One became a Republican and a B-list Texas oilman before abandoning drink, finding God, and following his father to the White House. The other turned against the war in which he was a decorated hero, before entering Democratic politics, spending the past two decades as senator for Massachusetts.

"Come November, voters will have a very clear choice" proclaims Mr Bush - he couldn't be more right. The choice extends even beyond two starkly different visions of the US role in the world, two different approaches to taxes, health care and the array of cultural issues that define American politics - gay marriage, guns, abortion and the rest.

In terms of character, too, the contrast could not be greater. Mr Bush, in his campaign persona at least, is an affable regular guy with a sense of humour, who mangles the language even more than most of us. Mr Kerry, on the other hand, projects elitism. Tall and gaunt, he might have stepped down from Mount Rushmore, long on gravitas but very short on laughs.

Those differences matter. The issues and trends in the American presidential mix can be impossibly complicated. Quite understandably, voters decide on the basis of character. A rule of thumb in modern US elections, is that the perceived nicer guy tends to win (Richard Nixon being the exception). In that respect, score it for Mr Bush.

From character flows a person's entire approach to governing. Mr Bush, famously, doesn't do nuance. For this utterly uncurious President, the world is black and white. In the Bush world view, it is a case of "either with us or against us."

Mr Kerry on the other hand does nuance, if anything to excess. All too often a Kerry speech is a symphony in greys. The habit reflects his knowledge of the issues, and the ensuing realisation that most things in life are more complicated.

"Thoughtful" is the adjective that often best defines Mr Kerry. But for audiences on the campaign trail, thoughtful is usually anything but exhilarating. For the Bush campaign the senator's "on the one hand, on the other" approach only proves his tendency to waffle - that he is a man congenitally unable to make up his mind, who cannot be entrusted with the job of commander-in-chief. Which leads, inevitably, to Iraq. For the first time in decades, the election will be shaped at least as much by foreign policy as by domestic issues such as jobs, education or health care. Hovering over it all will be the overlapping shadows of two wars, one 35 years ago in Vietnam, the other whose bloody aftermath make headlines today.

This year, the conflicts are inextricably entangled. If the US transfers power successfully to an interim Iraqi government and the violence subsides, then the debate about Mr Kerry's valour in Vietnam and Mr Bush's spell in the Texas National Guard will become irrelevant.

But if American soldiers continue to die and White House talk about installing democracy in the Middle East is exposed as cynical nonsense, then the disparity between Bush the launcher of wars and Bush the man who declined to serve in a war will be a constant subtext. The assumption is that 2004, like 2000, will be another desperately close affair. Others believe however it will not be so tight. Incumbents, their school of thought argues, usually win or lose by landslides.