Why Iowa shouts for John Kerry

Observations on the US primaries

I am in a school library and people are shouting at each other. This is one of the 1,993 meetings that make up the Iowa caucuses, won on 19 January by John Kerry, and the first test of support for the Democratic presidential nomination.

Iowans gather across the state in town meetings to deliberate about who should be the Democratic nominee, attempting to cajole and persuade their friends and neighbours to come to their candidates. At Roosevelt High School, the focus is on the 17 supporters of the left-wing congressman Dennis Kucinich. In the first expression of preferences, in which supporters bunch together in different corners of the room, his group is "non-viable": it doesn't have the minimum numbers needed to gain a delegate.

So the supporters of Senator John Kerry of Massachusetts, of the former Vermont governor Howard Dean, and of Senator John Edwards of North Carolina, are all trying to persuade the Kucinich 17 to come to them. An Edwards person, making a narrow political appeal, talks of a deal between Edwards and Kucinich. A Dean person highlights the anti-war consensus between Dean and Kucinich, but overplays his hand with aggressive courting. A Kerry person shouts: "Dean is going to get slaughtered [by George Bush]." A Kucinich person shouts that she wants a chance to get people to come to Kucinich because he is the most progressive candidate and it's important his voice is represented. Joined by some of the supporters of the Missouri congressman Richard Gephardt (a very non-viable ten people), she gets the four she needs for viability. Kucinich has his delegate.

Through this weird alchemy that is the Iowa caucuses, Kerry came back from the political dead. Written off at the turn of the year, polling just 15 per cent eight days before the caucus, his 38 per cent makes him the front runner as the candidates go into the New Hampshire primary on Tuesday. Dean faces a must-win vote there, after his third-place showing in Iowa.

What has gone wrong for Dean and right for Kerry? Dean's campaign manager says Kerry and Edwards, who took a creditable second place, co-opted Dean's populist message. True enough. In the final days of the campaign, Edwards electrified crowds with a message about the two Americas of today: "One for the privileged and powerful, one for everyone else . . . two governments: one for the insiders and lobbyists and one for the rest." Kerry called for "an economy based on people and products, not perks and privileges".

When Al Gore told the 2000 Democratic convention "We stand for the people not the powerful", he was derided by some of those associated with Bill Clinton for his "class warfare" message. Today, on tax cuts for the wealthy, the power of corporate interests and universal healthcare, the mainstream of the Democratic race has shifted to the left.

While Dean's message was being co-opted, he was hurt by several things. The capture of Saddam Hussein blunted the impact of his anti-war message; past statements suggesting hostility to Medicare sowed doubts about his consistency; above all, his status from December as presumptive nominee subjected him to attacks from opponents and scrutiny from the media, which he found hard to withstand. Becky Moser, a stay-at-home mum in Iowa City, told me: "Although Dean has a spark, he puts his foot in his mouth. Kerry is more electable."

But Dean remains apart in one important respect. Go to his rallies and they feel different - like a grass-roots movement. Many of his campaign volunteers - not simply hippie students, as critics suggest, but teachers, lawyers, wired workers and others - have been mobilised in support of Democratic politics for the first time. It is the kind of political network that the Republicans have spent a long time building. For whoever is the Democratic nominee, the challenge is to combine this deep commitment with the broad political support essential for victory.

Edward Miliband is visiting lecturer in government at Harvard and will shortly return to the UK Treasury to chair the Council of Economic Advisers