Zachary Taylor was an American military leader who served as the 12th president of the United States from 1849 until his death in 1850. Taylor was a career officer in the United States Army, rising to the rank of major general and becoming a national hero for his victories in the Mexican–American War. As a result, he won election to the White House despite his vague political beliefs. His top priority as president was to preserve the Union. He died 16 months into his term from a stomach disease.

The Mexican–American War, also known in the United States as the Mexican War, and in Mexico as the United States intervention in Mexico, was an invasion of Mexico by the United States Army from 1846 to 1848. It followed the 1845 American annexation of Texas, which Mexico still considered its territory because Mexico refused to recognize the Treaties of Velasco, signed by President Antonio López de Santa Anna after he was captured by the Texian Army during the 1836 Texas Revolution. The Republic of Texas was de facto an independent country, but most of its Anglo-American citizens who had moved from the United States to Texas after 1822 wanted to be annexed by the United States.