Obama casts his vote as campaign trail hots up in battleground states

The two candidates, locked in a neck-and-neck race which many have said is too close to call, are on the campaign trail in a last-ditch quest for votes across swing states.
President Obama is on a 40-hour, 7,000-mile eight-state marathon on Wednesday and Thursday. So far he's taken in a damp Iowa, a chilly Colorado and California at dusk.
Mitt Romney is also on the trail in the battleground states, appearing in Reno, Nevada, and Iowa, although his primary focus appears to be on Ohio, where he is planning a bus tour across the state and three rallies.