During the War of 1812, an invasion of Canada failed due to state militias being widely used, and U.S. troops were unable to stop the British from burning the new capital of Washington, D.C.. However, the Regular Army, under Generals Winfield Scott and Jacob Brown, proved they were professional and capable of defeating a major invasion by the regular British Army in the Niagara campaign of 1814. Between 1815 and 1860, the main role of the U.S. Army was fighting Native Americans in the West in the American Indian Wars, and manning coast artillery stations at major ports. The U.S. used regular units and many volunteer units in the Mexican–American War of 1846–48. At the outset of the American Civil War, the regular U.S. Army was small and generally assigned to defend the nation's frontiers from attacks by Indians. Following the Civil War, the U.S. Army fought more wars with Indians, who resisted U.S. expansion into the center of the continent.