On May 13, 1846, the United States Congress declared war on Mexico. Although
the Mexican-American War lasted only 18 months, its consequences were profound. Mexico
lost nearly half of its territory to the United States: Texas, California, New Mexico, Arizona,
Nevada, Utah, and Colorado. Some historians have described the conquest of Mexico City as
America's first step toward empire. More ominously, this war first raised the issue of whether
slavery should be permitted in the newly acquired territoriesan issue that would help speed
America toward the Civil War.

The United States at War is a collection of audio presentations that review the political, economic,
and social forces that have erupted in military conflict, and examine how the conflict resolved, or
failed to resolve, the forces that caused it.

Golden Gate University