USA HISTORY

Detailed explanation-1: -When the Mexicans fired on American troops in April 25, 1846, Polk had the excuse he needed. He declared, “[Mexico] has invaded our territory and shed American blood upon American soil, ” and sent the order for war to Congress on May 11. The act was a questionable one.

Detailed explanation-2: -Polk asked Congress for a declaration of war against Mexico following a skirmish between U.S. and Mexican troops in disputed territory. In his message to Congress, Polk claimed “Mexico has passed the boundary of the United States, has invaded our territory and shed American blood upon American soil."

Detailed explanation-3: -As war exists, and, notwithstanding all our efforts to avoid it, exists by the act of Mexico herself, we are called upon by every consideration of duty and patriotism to vindicate with decision the honor, the rights, and the interests of our country. . . .

Detailed explanation-4: -On May 12, 1846, the United States Senate voted 40 to 2 to go to war with Mexico. President James K. Polk had accused Mexican troops of having attacked Americans on U.S. soil, north of the Rio Grande. But Mexico claimed this land as its own territory and accused the American military of having invaded.