In 1789, when the First Congress met in New York City, the members traveled to the capital just as Roman senators two thousand years earlier had journeyed to Rome, by horse, at a pace of some five miles an hour. Indeed, if sea travel had improved dramatically since Caesar's time, overland travel was still so slow, painful, and expensive that most Americans lived all but rooted to the spot, with few people settling more than a hundred miles from the ocean (a mere two percent lived west of the Appalachians). America in effect was just a thin ribbon of land by the sea, and it wasn't until the...