First Lady sets stage for the Obama dream

Michelle Obama will highlight the human side of her husband tonight (Tuesday), as she makes the case for four more years of Barack Obama in the White House despite high unemployment and a sluggish economy.

In the opening speech of the Democratic Party's convention in North Carolina, the First Lady is expected to argue that the couple's tough upbringing enables them to understand the struggles of middle-class Americans.

With Obama virtually tied in the polls with Mitt Romney, his Republican opponent, Mrs Obama has become a vital asset to his campaign, which is working desperately to rekindle the grassroots enthusiasm of four years ago.

Stephanie Cutter, the deputy campaign manager for Obama, said that, as in 2008, the First Lady was "better at rallying support around the president than anyone else" and was working hard to set out Obama's "values and vision" for the country.

While the president's approval rating languishes at 43%, Mrs Obama's personal ratings have remained strong, thanks to her work to combat childhood obesity and protect veterans' rights. Some 66% of voters view her favourably, according to a Gallup poll.

She has been campaigning energetically, attending more than 80 events and fund-raisers since the spring.

Recalling their upbringing during a speech in Florida last month (August), Mrs Obama said growing up in a working-class home, struggling to better themselves and taking years to pay off their student debts had informed her husband's core values.

"Barack knows what it means when a family struggles," she said. "This is not a hypothetical for him. He knows what it means to work hard because you want something better for your kids and your grandkids. Like me and like so many of you, Barack knows the American Dream because he's lived it."

The implicit contrast with the privileged start in life enjoyed by Mitt and Ann Romney is clear. While Mrs Romney spoke last week of the couple eating "tuna fish and pasta" while studying at university, she previously admitted that they lived off the proceeds of a share portfolio given to Romney by his father, George, then chief executive of American Motors Corporation.

By contrast, Mrs Obama says, her husband's life experiences have shone through tough moments of his presidency, including the decision to bail out America's car companies and pressing ahead with health care reforms.

Democratic strategists hope that this week's convention, which culminates in Obama's address in a 74,000-seat stadium, will create a winning momentum.

They will be aiming to do better than Romney. A Gallup poll showed the Republican's performance in Tampa, Florida, last week had had the smallest "net impact" on his support - just two points - since the firm began recording it in 1984.

Romney's acceptance speech was rated the worst since Gallup began polling voter responses in 1996, when 52% of people said the speech given by the Republican nominee Bob Dole was "excellent" or "good". Romney scored positive responses from just 38%.