Swing Vote

"Swing Vote" follows the story of Bud Johnson, an apathetic, beer-slinging, lovable loser, who is coasting through a life that has passed him by. The one bright spot is his precocious, over-achieving 12-year-old daughter Molly. She takes care of both of them, until one mischievous moment on Election Day, when she accidentally sets off a chain of events which culminates in the election coming down to one vote--her dad's.

Source: Cinema Source