Kerry arrives to accept his crown. Now he must prove he's up to the challenge

After a five-day progress across America, John Kerry arrived here yesterday for his coronation at the Democratic convention, vowing to accept not only the nomination, but also "the responsibility and challenge" of his bid to win back the White House for his party.

After a five-day progress across America, John Kerry arrived here yesterday for his coronation at the Democratic convention, vowing to accept not only the nomination, but also "the responsibility and challenge" of his bid to win back the White House for his party.

"This has been an amazing journey," a beaming Mr Kerry told supporters waiting to welcome him at the harbour of his home town of Boston, surrounded by a dozen fellow Swift Boat veterans from Vietnam who had greeted the candidate as his campaign plane landed at the city's airport.

Today, as the convention reaches its climax, the Massachusetts Senator will deliver the most important speech of his career. He will tell thousands packed into the Fleet Centre and a prime-time national TV audience of his vision for America, and try to convince them that he is the man to whom they can entrust the country's leadership for the next four years.

Yesterday, he set out only the broadest of outlines, stressing the convention's theme of a "Stronger America, Respected in the World". Mr Kerry served notice that his speech, like most of those that preceded it this week, would be less about bashing the Bush administration, and focus on what a President Kerry would do if elected.

The Democratic candidate, whose national security credentials are a central issue in the campaign, was boosted last night by a dozen former senior US military commanders, including two former chairmen of the joint chiefs of staff, who endorsed him as a future commander-in-chief.

The boost came as the official roll-call vote of delegates of the states - once the stuff of real convention drama, but now a showy spectacular - formally delivered the nomination to Mr Kerry, and his vice-presidential running mate, Senator John Edwards of North Carolina.

Far more important, for the second night running, the party's senior figures set about telling the country about a presidential candidate who is a less- than-stirring orator, and still a largely unknown quantity to many Americans.

On Tuesday, Mr Kerry's wife Teresa, whose unpredictable ways have created some suspense in an overwhelmingly scripted proceedings, described her husband as "the best man to defend America at home and abroad". He would "always be first in the line of fire", just as during his service in Vietnam.

But the Mozambique-born Mrs Kerry, the Heinz food products heiress and philanthropist, whose outspokenness and imperious style on occasion scares her advisers stiff, won her biggest laugh right at the start, when she noted that "it will come as no surprise that I have something to say".

She then proceeded to greet the conventioners in Spanish, French, Italian and Portuguese as well as English, before giving a policy speech astonishing by the normally demure standards of First Ladies.

She implicitly criticised the Bush White House for trampling on environmental concerns, and spoke of her husband's determination to make the United States more energy self-sufficient, "so that no American boy or girl will go to war because of our dependence on foreign oil".

And in a Kerry administration, she said: "Global climate change and other threats to the health of our planet will begin to be reversed".

Whether Ms Heinz Kerry will be a help or hindrance to her husband is hotly debated here. But, on Tuesday night, that soft foreign accent helped make her a smash. Democratic strategists believe that her demands for greater equality of opportunity and treatment for women will be highly appealing to female voters in the 2 November election.

She drew from Abraham Lincoln to promise that Mr Kerry would summon "the better angels in ourselves", and declared that Americans were seeking a leader who could draw again "on the mystic chords of our national memory". And, she added in down-to-earth fashion: "I think I've found that guy; and I'm married to him."

But the earlier rave reviews went to the keynote speaker, Barack Obama, the 42-year-old Kenyan-American and Democratic senate candidate for Illinois, who electrified the convention with his call for a healing of the national divisions fostered by the Bush administration. "There's not a black America and white America and Latino America and Asian America; there's the United States of America," Mr Obama said, highlighting his own multi-ethnic origins.

Last night, Mr Edwards took the spotlight with his own acceptance speech. Like Mr Kerry, he vowed that a new Democratic administration would mend America's fences with the outside world. He also took up anew the theme that served him so well in the primary season, where he was the last serious challenger to Mr Kerry before dropping out in March, promising to close the gap between "the two Americas", divided by wealth, education and health care coverage.

Before the speech, the vice- presidential nominee's advisers stressed that his tone would not be specifically anti-Bush. Instead, Mr Edwards, whose "happy warrior" political persona contrasts with the very thoughtful but often dour image projected by Mr Kerry, would stress the positive, setting out a constructive agenda for improving America.

But Mr Edwards, reckoned to be the party's finest natural campaigner since Bill Clinton, also deployed his trial lawyer skills at selling a case in the courtroom to that of selling John Kerry to the country, again helping draw a portrait of a potential president who is a mystery to many voters.