Question

Why did the U.S. go into war with Mexico?

Answer 1

In 1846 a dispute over the border between texas and mexico resulted in armed conflict and the mexican-american war began

Answer 2

Texas and Mexico had a dispute over territory and Polk moved U.S. troops into a place that Mexico said WAS NOT in Texas. They effortlessly presumed that the land was theirs. Therefore, the Mexican army attacked them.