PHOTO GALLERY: Candidates, voters head to polls across the nation

President Barack Obama is applauded as he visits with volunteers at a campaign office the morning of the 2012 election in Chicago.   |  CAROLYN KASTER/The Associated Press

Republican presidential candidate, former Massachusetts Gov. Mitt Romney and wife, Ann Romney, vote in Belmont, Mass., on Tuesday.   |  CHARLES DHARAPAK/The Associated Press

Carol, left, and Amon Burton, Obama campaign volunteers, place Election Day signs on Lamar Boulevard before polls open on Tuesday morning in Austin, Texas.   |  TAMIR KALIFA/The Associated Press

Snow surrounds the polling precinct in Terra Alta, W.Va., as Peter Hough heads to work after casting his ballot on Election Day.   |  DAVE MARTIN/The Associated Press

Vice President Joe Biden, accompanied by his son Beau Biden, his wife, Hallie, and their daughter Natalie, stands in line to cast his ballot at Alexis I. duPont High School on Tuesday in Greenville, Del.   |  MATT ROURKE/The Associated Press

Republican vice presidential candidate, Rep. Paul Ryan, R-Wis., votes with his children, Sam and Liza, as his wife, Janna, second from left, votes with Charlie, at the Hedberg Public Library in Janesville, Wis., on Tuesday.   |  MARY ALTAFFER/The Associated Press

U.S. Sen. Claire McCaskill, D-Mo., votes at her polling place, Kirkwood Community Center, on Tuesday in Kirkwood. McCaskill is running for re-election against Republican challenger Rep. Todd Akin, R-Mo.   |  JEFF ROBERSON/The Associated Press

Missouri Senate candidate, Republican Rep. Todd Akin, right, votes at his polling place, Star Bridge Christian Center, on Tuesday, in Wildwood. Akin is running against incumbent Sen. Claire McCaskill, a Democrat.   |  Jeff Roberson/The Associated Press

Leslie Fabian concentrates as she votes electronically at the 24-hour Su Nueva Laundromat in Chicago's 13th Ward on Tuesday in Chicago.   |  Charles Rex Arbogast/The Associated Press