By the time most Americans see the presidential candidates on the campaign trail, they are practiced performers surrounded by a platoon of staffers and a brigade of reporters. But on their initial forays into Iowa and New Hampshire in 2002 and early 2003, their entourages were decidedly unpresidential--just an aide or two, perhaps a local reporter, and the candidate himself. Their motorcades were literally one-car caravans; their campaign stops, small...