Politics was not at the forefront of Candice Mason's mind as she loaded bags of groceries into her shabby green Honda Accord outside a Wal-Mart store in Toledo, Ohio.

She was in a hurry to get home before rush hour to feed her eight-year-old son, Aidan, who hovered at her side playing with a toy pellet gun. Pressed to answer who she would vote for in November, she sounded unsure. "Probably Obama because we need a change," she said. "My only doubt is whether he has enough experience."