Conference will be family affair as ordinary Americans are courted

Under the theme of One Nation, the 44-year-old Harvard-trained daughter of a middle-class black family from Chicago will describe how her husband's life has been one of "struggle, opportunity and responsibility". Following the mother-of-two on to the podium will be Maya Soetero-Ng, Barack Obama's half-sister, and Craig Robinson, Mrs Obama's older brother, a basketball coach, who will also make contributions about the candidate's "very American story".

There will also be ordinary folk, too, such as Mike and Cheryl Fisher from Indiana, who will underline the effects of the credit crunch.

Mike, a father-of-three, is an Amtrak mechanic facing being laid off. "I'm just a poor railroader," Mike will say. "I've got a small house and a family I'm trying to raise. Barack and Michelle can relate to that because of their upbringing."

The fact that John McCain, 72, the Republican presidential candidate, could not recall how many homes he had - he has eight - will be the inherent contrast in the message Obama is peddling: he is interested in ordinary Americans while McCain, a multi-millionaire, is primarily interested in cutting taxes for the rich.

Obama's background has been and will continue to be an important factor for many undecided American voters, particularly in the more conservative parts.

The son of a black Kenyan father and a white Kansan mother who spent his early school years in Muslim Indonesia, Obama, 47, has admitted his mixed race and non-traditional background are challenging for some people.

"I'm asking a lot of the American people and I know that," he admitted recently. "My biography is not typical of a modern American president."

The Kennedy iconography will again be present in the form, albeit indirectly, of Edward Kennedy. There will be a tribute to the Massachusetts senator as well as a videotaped message from the 76-year-old, who is suffering from brain cancer.

Other speakers on the opening night will include Nancy Pelosi, Speaker of the House, and Jesse Jackson, the civil rights activist and sometimes firebrand campaigner.

Last month, Mr Jackson, who failed in his own bid for the Democratic presidential nomination in 1984, apologised for "regretfully crude" remarks he made about Obama when he whispered that he wanted "to cut his nuts off" because he felt his colleague was "speaking down to black people".

Tomorrow, Hillary Clinton, the failed Democratic contender, will be the main prime-time speaker when the convention's theme will be "renewing America's promise". After the sometimes bitter battle to be the Democratic nominee, the ex-First Lady will be key in healing wounds and trying to convince many of her supporters, who are toying with backing McCain, to stick with Obama.

The issues raised by a raft of governors and senators will be ones around the struggle many middle-class Americans are engaged in on the back of the credit crunch.

On Wednesday, the key event will be the address by Delaware's Joe Biden, the vice-presidential nominee, who is seen as more aggressive than Obama in duffing up the Republicans and will become his party's attack-dog.

The general theme of the night will be securing a tough foreign policy - Biden is seen as having more strength on foreign affairs than Obama - that makes "America stronger and safer". Among those addressing the convention will be Bill Clinton, the former president, who still possesses the capacity to overshadow any other speaker.

The final day on Thursday will be dominated by Obama's speech under the campaign theme of Change You Can Believe In.

While the convention proper at the 21,000-capacity Pepsi Center is not open to ordinary Denverites, the organisers have shifted the venue for the main event to Invesco field, home of the Denver Broncos, which can hold 75,000 people.