Manifest Destiny & U.S.-Mexico War (1846-1848)

Manifest Destiny

Belief that the U.S. was destined by God to expand across North America

Frederick Jackson Turner’s Frontier Thesis

Argument that American democracy developed through frontier expansion

Manifest Destiny and race

Promoted white supremacy and justified the displacement of Indigenous and Mexican populations

Cause of the U.S.–Mexico War

Territorial disputes and U.S. expansionism after Texas joined the U.S

Military advantage of the United States

Better organization and fewer political conflicts among leaders

Mexican weakness in the war

Political instability and competition among generals

Occupation of Mexico City

U.S. troops captured the capital after advancing deep into Mexico

Chapultepec Castle (1847)

Site of Mexico’s last major resistance before defeat

Impact of the war on Mexico

Seen as a humiliating national trauma revealing military weakness