U.S. has not been involved in a war on our mainland with a foreign power since the 1846–1848 Mexican War, which we ourselves initiated. Even mere raids on the U.S. mainland have been negligible: just a British raid on Washington during the War of 1812, Pancho Villa’s raid on Columbus in New Mexico in 1916, one shell fired by a Japanese submarine in World War Two onto the U.S. coast at Santa Barbara, and six American civilians killed by an explosive-laden balloon launched from Japan also during World War Two.
