What were the most serious accusations against the Mexican American War?

Answer 1

There were no good reasons for the Mexican War. It was fought to acquire land that became the American Southwest when negotiations to buy the land failed. The pretext that began the war was trumped up. Van Buren sent US troops into disputed territory to provoke an armed response. When it came, he invaded in retaliation for the attack which he provoked. The justification given was Manifest Destiny: that America deserved the land from coast to coast because it was destined to have it [a tautological argument if ever there was one]. It wound up provoking a constitutional crisis concerning the admission of slave states into the union which ultimately led to the Civil War. Granted American troops were outnumbered, but they were well-armed, well-led, well-equipped fighting force, and the Mexicans, though numerous, were, for the most part, poorly led, poorly trained, poorly armed, and poorly equipped. Besides shear numbers, there only real advantage was fighting on their home turf.