However much the extending of America's borders may have seemed like destiny at the time, much of the process was not as noble as its early proponents declared, and in the Southwest it represented at least partially a deliberate land grab. The work of one rather eccentric idealist, a Virginian named Nicholas Philip Trist, allows modern Americans to consider what happened during the years 1846-48 without what one writer called "a thorough revulsion." Nicholas Trist (1800-74) was one of those rare public figures who really live dangerously, prepared to risk everything for principle. Generally...