1845-1848: Mexican-American War - James K. Polk, despite not having a declaration of war, sent US troops into dispute territory between the Nueces and Rio Grande, provoking Mexico, a nation already ready to declare war. Later, pointing to a Mexican reaction, Polk asked for and received a declaration of war despite impassioned speeches by Abraham Lincoln on the contrary. The provocation of a war likely for the purposes of the annexation of territory including much of the American Southwest was a significant (jan 1, 1845 – jan 1, 1848)
Added to timeline:
Date:
jan 1, 1845
jan 1, 1848
~ 3 years