President Barack Obama hugs a woman in the crowd after addressing the Labor Day celebration in Detroit, Mich., Sept. 5, 2011.

President Barack Obama hugs a woman in the crowd after addressing the Labor Day celebration in Detroit, Mich., Sept. 5, 2011.

President Barack Obama greets a man in the crowd after addressing the Labor Day celebration in Detroit, Mich., Sept. 5, 2011.

President Barack Obama greets a man in the crowd after addressing the Labor Day celebration in Detroit, Mich., Sept. 5, 2011.

President Barack Obama prepares to take the stage on the floor of the Chrysler Auto Plant in Detroit, Mich., July 30, 2010.

President Barack Obama prepares to take the stage on the floor of the Chrysler Auto Plant in Detroit, Mich., July 30, 2010.