In the days following the destruction of the U.S. Pacific Fleet at Pearl Harbor, Hawaii, many military officials and West Coast residents braced themselves for a Japanese attack on the Pacific coast. Their fears were not completely unfounded. The West Coast's main line of defense was sent to the bottom of Pearl Harbor by planes from a large Japanese aircraft carrier strike force that was now roaming the Pacific Ocean unopposed. An attack on the defenseless West Coast appeared imminent and the threat of an invasion sparked a wave of intense anti-Asian sentiment in California, Oregon, and Washington.

Reasoning that the 110,000 residents of Japanese ancestry living on the West Coast might prove friendly to a Japanese invasion force, many prominent journalists, military officials, and politicians began to agitate for their removal. The press teemed with stories about "fifth column" saboteurs aiding in...