Covering a presidential campaign can feel like this: Stop in one town, watch a candidate talk and shake a few hands, then move along to the town up the road. There went Toledo, Iowa. So that was Independence, Iowa? The crowd back in Cedar Rapids sure was big. It can be easy to see these scenes as photographs passed in a gallery, or a set of props neatly arranged for a candidate to make a pitch. The reality is, these scenes are full of people with a story to tell — not only of whom they may vote for, but...