August 28, 2012
Pablo Monsivais photo

President Barack Obama greets supporters on the tarmac upon his arrival at Des Moines International Airport in Des Moines, Iowa, Tuesday, Aug. 28, 2012.

Carolyn Kaster photo

President Barack Obama speaks about Tropical Storm Isaac, Tuesday, Aug. 28, 2012, in the Diplomatic Room of the White House in Washington.

Pablo Monsivais photo

President Barack Obama and Sen. Tom Harkin, D-Iowa arrive at Des Moines International Airport, Tuesday, Aug. 28, 2012, in Des Moines, Iowa.

Pablo Monsivais photo

President Barack Obama speaks during a campaign event at Iowa State University, Tuesday, Aug. 28, 2012, in Ames, Iowa.

Pablo Monsivais photo

President Barack Obama wipes his face at a campaign event at Iowa State University, Tuesday, Aug. 28, 2012, in Ames, Iowa.

Nati Harnik photo

President Barack Obama arrives to a campaign stop in Ames, Iowa, Tuesday, Aug. 28, 2012. The president’s event in Ames, home of Iowa State University, is part of a tour through college towns.