Charlotte, N.C. ? President Barack Obama’s selection of this Southern city for the 2012 Democratic convention signals he will try to reassemble his diverse coalition of 2008 supporters and fight for the conservative-leaning states that helped him win the White House.

The Democratic National Committee announced the selection of Charlotte on Tuesday, rejecting bids by a trio of Midwestern cities hit hard by the recession — Cleveland, Minneapolis, and St. Louis — in favor of the more economically stable North Carolina.

With the economy certain to dominate Obama’s re-election bid, North Carolina’s long-term industrial transformation — from tobacco, textiles and furniture to research, energy and banking — also plays into what may be the centerpiece of the Democrat’s re-election bid, a call for America to focus on innovation to compete in the changing global marketplace.

The convention’s apparent theme — The People’s Convention — indicates that the president will try to rekindle the grass-roots flavor of his groundbreaking 2008 bid.

“This will be a different convention, for a different time,” first lady Michelle Obama wrote to supporters Tuesday in an e-mail that disclosed the city where Democrats plan to nominate Obama and Vice President Joe Biden for a second term. She said the gathering would be “a grass-roots convention for the people” and promised to pay for it in a different way. But she provided no specifics on either point.

The announcement of where Obama will formally kick off his re-election campaign was the latest step in the president’s efforts pointing toward 2012. He has shifted political aides out of the White House, authorized a campaign headquarters for Chicago and started repositioning himself as a president who governs from the center of the ideological spectrum.

He must try again to cobble together the voting blocs that helped him win across the country, including in such normally Republican states as North Carolina, Virginia and Indiana. He became the first Democratic presidential candidate in decades to win those. And he did it by appealing to a wide swath of voters, some of whom have since soured on him.

Independent voters were critical to his victory in 2008 but have tilted away from him over the past two years. Sporadic-voting minorities and young adults who backed him in droves can’t be automatically counted on to do the same next year. Neither can people who cast ballots for the first time, or disenchanted Republicans who crossed over to vote for Obama.