The Campaign: Obama targets undecided voters in tour of key battleground states

Buoyed by a triumphant Democratic convention on which he is counting to generate a "bounce" in the opinion polls, Barack Obama and his vice-presidential running mate Joe Biden launched a four-day tour of key battleground states yesterday.

As the Republicans seize the the national stage and the limelight, opening their convention in St Paul, Minnesota on Monday, Mr Obama will be focusing on the fight to persuade and reassure those voters who still harbour doubts about the prospect of a black president who is also a liberal.

Accompanied by their wives Michelle Obama and Jill Biden, their first port of call is the small town of Beaver, Pennsylvania, to see if any of the magic of the convention has rubbed off.

Pennsylvania is where Hillary Clinton badly bloodied Mr Obama in the primary votes, by stirring up the suspicions of people in the depressed old steel towns. But now, with the Irish-Catholic barnstormer Mr Biden by his side, Mr Obama is hoping for a better reception from the people he once famously described as "bitter" and "clinging" to guns and religion when times were hard.

They did not forgive him in the primary and the Obama campaign hopes that the "all in the family" scenes, with which they wrapped up the Denver convention, will soften the hearts of rural white voters, especially women.

The offensive then moves to the rust belt state of Ohio, scene of another humiliating defeat for Mr Obama at the hands of Mrs Clinton. At the Cleveland Convention Centre tomorrow night, they will celebrate the life of the much-loved Congresswoman Stephanie Tubbs Jones, who died recently. The pace then hots up as the Democrats criss-cross Ohio before reaching Michigan, another must-win state if they are to oust the Republicans from the White House.

In his convention speech on Thursday, Mr Obama told stories of economic heartbreak. One was about a machinist in Indiana who wept as he packed up the plant he had worked in all his life and saw it shipped off to China. Another was about a hardworking nurse in Pennsylvania who was struggling to get by.

Mr Obama has held out specific plans for generous tax breaks for workers like these, pushing back against charges from the Republican attack machine that he is all style and no substance. Mr Obama also took the fight directly to John McCain with a directness that cheered many Democrats. Now the challenge will be to see whether he gets a serious bump in the polls or whether the Republican counter attack, that he is just another tax-and-spend liberal, pays off.

As he travels through the swing states, Democrats are confident that they can win the debate on many of the bread and butter issues. But the fear is that their opponents will set the terms of debate on such issues as patriotism, race, character and experience. Mr Obama will rely on casting Mr McCain as a clone of the deeply unpopular President Bush.

When his presidential campaign was in danger of being wiped off the map by Mrs Clinton last November, and he was far behind in the polls, he delivered a rousing speech at a fundraising dinner in Des Moines, Iowa. In it, he evoked the courage of those of the civil rights years who had "stood up" to "somehow manage to change the world".

Nine months later, he delivered a similar message in a Colorado stadium. And it was projected straight into the living rooms of his target audience in the swing battleground states.

The verdict: how the speech went down

Oprah Winfrey

I cried my eyelashes off... I think it's the most powerful thing I have ever experienced. He's not an African-American candidate. He's a candidate for Americans.

Wesley Pruden, of 'The Washington Times'

Barack Obama never looked more like the American Idol than last night, standing before the Athenian columns of his Golden Temple of Obama the Anointed. Television viewers were no doubt puzzled that there were no telephone numbers crawling across the bottom of the screen, urging them to cast their votes now at a dollar a pop.

Rev Bernice King, daughter of Martin Luther King

Forty-five years ago today, my father delivered his "I Have a Dream" speech. We witness in part what has become of his dream, the acceptance by Barack Obama of the presidential Democratic nomination... a nomination decided not by the colour of his skin, but by the content of his character. This is one of our nation's greatest defining moments.

Leslie Sanchez, Republican strategist and former adviser to President Bush

You can give Obama an "A" for his great oratory. But once you remove the gloss, tonight's speech was the same tired Democratic rhetoric of the past 30 years.

'USA Today' Editorial

He repeated his commitment to make the country energy-independent in 10 years – a potentially inspirational goal but one that some think is neither technologically nor politically possible.... While Obama's vision is more detailed than McCain's, it is still a work in progress.

David Gergen, White House adviser to Presidents Nixon, Ford, Reagan and Clinton

I saw Obama's speech tonight as a political masterpiece... it was in many ways less a speech than a symphony. I also sensed that we saw an Obama who is growing into a new, more mature leader – stronger, tougher, harder-hitting than he had appeared only a few weeks ago.

Larry Elder, radio talkshow host

You cannot nationalise health care, promise a world-class education for every man, woman and child, set up a $150bn fund for alternative forms of energy and get it all from the so-called rich. The money isn't there.

Mark Halperin, 'Time' magazine

Hitting Bush and McCain like a pro, he damned with faint praise, mocked with humour, and emphasised issues on which the Republicans are vulnerable.

For rolling comment on the US election visit: independent.co.uk/campaign08