Kerry meets his Waterloo in Iowa, the vital battleground at the heart of the nation

Separated by fewer than 60 miles of the American heartland yesterday, George Bush and John Kerry vigorously attacked each other in Iowa, one of the handful of crucial battleground states that are likely to decide the outcome of the presidential election, now less than two weeks away.

Separated by fewer than 60 miles of the American heartland yesterday, George Bush and John Kerry vigorously attacked each other in Iowa, one of the handful of crucial battleground states that are likely to decide the outcome of the presidential election, now less than two weeks away.

In Waterloo, Mr Kerry delivered a long and detailed speech on foreign policy, outlining how he would deal differently from Mr Bush with the issues of Iraq and terrorism, stressing the need to display international leadership and build coalitions. In Mason City, less than an hour's drive to the north-west along almost empty roads, Mr Bush portrayed his challenger as misguided and confused.

Mr Kerry said: "America is fighting, and must win, two wars: the war in Iraq. And the war on terror. President Bush likes to confuse the two. He claims Iraq is the centrepiece of the war on terror. In fact, Iraq was a profound diversion from that war and the battle against the enemy. It was a profound diversion from Osama bin Laden and al-Qa'ida."

As if in direct response, Mr Bush, speaking shortly afterwards, declared: "My opponent ... misunderstands our battle against insurgents and terrorists in Iraq, calling Iraq a diversion from the war on terror."

If nationwide polls show the two candidates to be neck and neck, perhaps with Mr Bush with his nose in front, the surveys in Iowa show that the battle for the state's seven electoral votes is even closer. Four recent polls in this state of gently undulating farmland and small towns - which in 2000 Al Gore won by just 4,144 votes out of 1.3 million cast - suggest the men are essentially tied.

As proof of how important both sides believe Iowa will be on 2 November, Mr Bush's visit yesterday was his 20th to the state during his presidency and the fourth in the past fortnight. Mr Kerry's speech in Waterloo was his third Iowa visit in the same two-week period. Their running mates, Dick Cheney and John Edwards, have also paid several visits to Iowa, politically and geographically smack in the middle of the US.

Mr Kerry delivered his foreign policy address in the Five Sullivan Brothers Convention Centre, named after five brothers from this small town who died together on 13 November, 1942, when their naval ship, the USS Juneau, was sunk off Guadalcanal in the Pacific.

"It's an honour to be here," Mr Kerry said. "We all know about those five brothers who were lost in the same ship in the Second World War, and what that kind of sacrifice means to American families and to our nation. Like the countless others who've given their lives in service, they are the greatness of America."

Echoing the muscular language he used at the Democratic National Convention, Mr Kerry outlined a series of measures he said he would undertake as president to deal with terrorism: a reform of intelligence, a 40,000-troop expansion of the army and an investment in the US special forces to allow them to better take on terrorists.

"Make no mistake, our troops are the best-trained and best-led forces in the world, and they have been doing their job honourably and bravely," he said. "The problem is that the commander-in-chief has not being doing his. If President Bush cannot recognise the problems in Iraq, he will not fix them. I do recognise them and I'll fix them."

He added: "This President says he's a leader. Well Mr President, look behind you. There's hardly anyone there. It's not leadership if we haven't built the strongest alliance possible and if America is almost alone."

The foreign policy speech by the Massachusetts Senator was almost certainly crafted to counter recent attacks on him by Mr Bush and, most pointedly, by Mr Cheney who raised the spectre of the US being attacked by nuclear weapons; he claimed that Mr Kerry would not be able to deal with such a scenario.

Yesterday there was no letup from the Bush camp. In Mason City, Mr Bush again accused Mr Kerry of failing to understand the importance of the war in Iraq. "The next commander-in-chief must lead us to victory in this war and you cannot win a war when you don't believe you're fighting one," he said.

For Mr Kerry, of course, Iowa brings back fond memories. Back in the freezing days of late January, he won the state's Democratic primary contest, gaining the momentum that allowed him to go on and secure the party's nomination for president. While Ronald Reagan, who once worked as a sports announcer in the state capital, Des Moines, was the last Republican president to win Iowa, Democrats are aware how close the contest is this year. Since 2000, they have increased the number of registered supporters by more than 48,000; the Republicans have added fewer than 7,000.

Yet, a stroll around Waterloo yesterday morning, suggested anecdotally at least, that locally there were plenty of supporters from both camps.

Jim Baumeister, 68, a military veteran and retired accountant, was carrying a pole, attached to which were several plastic beach sandals, a reference to Mr Kerry's alleged habit of flip-flopping. "I can't stand Kerry, because of what he did when he got back from Vietnam," he said. "I served in the military for four years; you just can't do that [denounce the war]," he said. "He is running nothing but a negative campaign."

By contrast, Jeanne Lueders, 49, could hardly have offered more support for Mr Kerry, for whom she voted during the Democratic primary elections. She said: "I made my mind up a long time ago. I am concerned about the high cost of prescription drugs. I have to take medicine to keep me alive; my mother, who is 80, has to take medicine." She added: "I voted for him in January. I liked his calmness. He is very direct. He did not seem as if he was peddling something."