The two most harrowing parts of any trip to Vietnam, where the war against the United States - even 40 years on - still dominates, are the Cu Chi tunnels north of Saigon and the Mekong Delta. As you emerge from crouching in the warren of once deadly, booby-trapped foxholes and command centres, there are decaying photos, pinned on trees and walls, of Vietcong soldiers with their decorations for being effective 'American killers'. The war's savagery and brutality could hardly be more effectively conveyed. But as terrifying and futile as trying to penetrate the Vietcong tunnel system was trying to prevent the Mekong Delta - Vietnam's rice basket - from falling entirely under Vietcong control. The maze of slow-moving interlocking rivers and canals with dense, overhanging foliage offered perfect cover for attacks on US patrol boats.  Time and again, as we navigated today's tourist attractions of floating markets and shrines, I thought how it must have felt in a different time to be stalked by an enemy who had such amazing cover so close to their targets. But it was in this delta that Senator John Kerry, then a lieutenant, turned his Swift boat to attack his tormentors directly, going ashore to kill the Vietcong soldiers who were armed with B40 rocket launchers that could sink a US boat.  Vietnam veterans now hold a particular place in US life. They may have fought in America's most controversial war before Iraq, but their physical and psychological wounds are testimony to the fact they served their country even in a futile cause. (Their war culminated in an ignominious scuttle but strategically it bought the rest of South-East Asia more than a decade in which to deliver the capitalist Asian miracle; the immediate war was lost but a bigger struggle for economic power was eventually won.)  It is testimony to the profound dominance of conservatism on the American national consensus, with the noxious charge of not being patriotic that is levelled by Bush against any critic, that the best way any liberal voice can fireproof himself against such a charge is to play the Vietnam vet card. As Kerry says, in order to be heard about the rollcall of domestic issues that concern ordinary Americans, any Democratic presidential candidate has to get past the security issue; being a decorated Vietnam vet offers Kerry the passport.  So now for one safe-ish forecast and one risky prediction, which I wish I had written last May when I first met the Kerry camp. Kerry is going to win the nomination to be the Democrat presidential candidate and I think he will go on to beat George Bush. American democracy may have its grievous defects - the role of money, the grotesquely gerrymandered congressional districts, the low turnouts and all the rest - but it still retains a core functionality.  Bush led his country into an illegitimate war for trumped-up reasons; the consequent morass is already costing more than $100 billion, many American lives and profoundly compromising US and Western interests. In a democracy, you pay for such fundamental misjudgments with your job and Bush will pay with his.  The American democratic process in this respect is showing its underlying smartness. Howard Dean's emergence as the Democratic front runner for President last year was very important. He articulated the raw anger that the Democrat base felt at Bush and he reminded the Democratic establishment about core Democratic values.  If you weren't stirred by Dean's rallying call, you had cold blood. But it isn't and wasn't good enough to get mad - Democrats have to get even.  Too much is at stake in this election to risk the indulgence of a candidate who, however fiercely he may proclaim his commitment to fiscal conservatism and toughness on crime, is now so far from the centre as Dean, and who, moreover, does not have the cachet of having seen military service. In January, faced with the sobering truth that 2004 is an election year, Democrat voters have turned their back on Dean's rage and embraced the war hero. They want their case to get to first base.  To British eyes, the quality of speech-making and capacity to stir emotions in the state primaries, where the rival candidates pitch for voting support in August's convention, has been eye-opening. John Edward's invocation of two Americas and advocacy of an effective social contract for every American is high octane and passionate. But both Howard Dean and John Kerry, with his call for a 'Real Deal', are not far behind. They have found a language to talk social-contract politics, even if they never mention the term; they indict the corruptions of American capitalism; they celebrate the capacity of public action to offer remedies.  And Kerry, I am glad to note, has got the bit between his teeth over sky-high university tuition fees pricing students from ordinary backgrounds out of college education. It was the statistics about America's declining social mobility and the now incredible debt that students have to assume that interested his chief of staff most when we met. I thought and still think that this is an undersung issue the Democrats can use to appeal to middle-class swing voters.  So much is going for the Democrats - demography and the growth of the black and Hispanic vote, the social libertarianism of the cities, the insecurities of American life, the decline of opportunity and the massive failures of Bush's foreign policy - that what effectively stands between them and the presidency is the South, a hawkishly conservative media and atavistic fear of terrorism.  Bush's position is much weaker than it seems; even in the South, voters are worried about their children leaving college with debts of $50,000 or more and the rank unfairness of American society. The conventional wisdom is that America is polarised along 50/50 lines; it is certainly polarised, but the split is more like 60/40 or even 65/35 - and with the right candidate who can escape the tag of being a wimp because he is not conservative, there is every chance of enlisting that majority.  Bush will certainly narrow the gap with a blitz of what will be some of the nastiest political advertising yet sanctioned in the US, but I still think this is an election the Democrats can win.  Which is where Kerry's experience in Vietnam is so vital; he can argue for the importance of legitimacy in fighting wars, of being on the right side of the moral argument and of the need for genuine international coalitions without being cast as another draft-dodging liberal; indeed, he can hurl back that charge with interest.  The pity is that Bush will wheel out Blair as proof that Kerry is wrong, a measure of how badly Blair has played every aspect of Iraq. Democrats don't want to see or hear from him this year in the US. I don't blame them. That Blair is a liability to the progressive tradition on both sides of the Atlantic is a damning indictment. If the Democrats want him to be silent, then silent he'd better be. We want Kerry as President, too.