The U.S. Army held Mexico City and expansionists cried 'All Mexico!' So why did America take only the thinly settled north and hand the heartland back? The episode sets out the evidence for the racism thesis in Calhoun's claim that America was 'the government of a white race,' then tests it against the free-soil versus slave-power fight and fear of guerrilla occupation. Nicholas Trist defies his recall to sign the Treaty of Guadalupe Hidalgo.
Historians disagree about how much race did on its own versus the free-soil fight over slavery and the fear of guerrilla occupation, and the episode lays out the three causes without ranking them.



