CHARLOTTE, N.C. -- President Barack Obama is spending the day at a hotel in Charlotte, N.C., tweaking the speech he'll give tonight at the Democratic National Convention, and consulting with advisers.

He's arranged an afternoon conference call with supporters who were hoping to see him speak at an outdoor stadium tonight, but who will now miss that chance because the speech has been moved indoors.

Obama tonight will take people back to the start of his presidency to make a case why their lives are better, but his bigger imperative is to sell himself as better for middle-class America than Republican Mitt Romney.

He's expected to whittle the election down to a choice between economic opportunity for all or, as he says, Republican ideas that favor the few.