The conflict lasted less than two years, but the repercussions shook both nations for much longer.
Having already lost Texas, the still newly independent Mexico was unprepared to defend their northern territories. The US plowed forward through to California with a sense of manifest destiny. While the US fought to gain more land, however, the war splintered the North and South; many Americans saw the war as an unjust theft of Mexican land and knew that the South’s reliance on slave labor would further establish this divisive injustice in America. While the US won this war, this short history reveals how the division it sowed among its people led to the Civil War, the bloodiest conflict in American history.