Michelle Obama won plaudits from across the political divide on Wednesday for a speech in which she told Americans that her husband felt their pain and deserved four more years in the White House.
Promising struggling voters that "Barack knows the American dream because he's lived it", the self-styled "Mom-in-chief" urged those frustrated at his performance to be patient.
"Change is hard, and change is slow, and it never happens all at once," she told 20,000 supporters in a basketball stadium in Charlotte late on Tuesday.
"But eventually we get there - we always do".
In a personal address to the Democratic convention, Michelle assured supporters that Obama was "still the same man", adding: "I love my husband even more than I did four years ago."
Her remarks prompted roars of "four more years". Speaking at an event yesterday, Michelle said: "The energy, the enthusiasm that we saw last night made it clear that folks are pretty fired up."
Her speech drew praise even from Karl Rove, the former White House adviser to George W Bush, the former Republican president, who conceded that it was "very well delivered".
David Gergen, a political consultant who worked for Republican presidents Richard Nixon and Ronald Reagan, told CNN news channel: "If they have two more nights like this, they can probably break this race open."
She carried out a thinly veiled attack on Mitt Romney, her husband's Republican challenger, who claimed to have the necessary experience for the White House due to his success at Bain Capital, the private equity firm where he made a $250 million (£160 million) fortune.
"The issues that come across a president's desk are always the hard ones - the problems where no amount of data or numbers will get you to the right answer," said Michelle.
Recalling days when they were "so young, so in love, and so in debt", Michelle said she and her husband had struggled to repay their student loans as young graduates. Ann Romney said in a 1994 interview that she and her husband paid their way through university using profits from stockholdings given to Mitt Romney by his father, which they would "sell off a little at a time".
However, Michelle drew fire from the Romney campaign for appearing repeatedly to contrast the backgrounds of the two candidates.
Paul Ryan, Romney's vice-presidential running mate, said: "While Team Obama continues its campaign of fear and division, we are talking about the big issues that Americans face."
Michelle's accomplished delivery - a marked improvement since her 2008 convention speech - prompted suggestions that she might follow Hillary Clinton, the US secretary of state, into politics after serving as First Lady.
However, Jodi Kantor, the author of a book on the Obamas' relationship, said: "Sorry people, Michelle Obama will never run for public office. If she does, I will eat every page of my book."