Content Warning: This section contains references to the deadly military attack on Pearl Harbor. It also mentions the subsequent incarceration of Japanese Americans in US concentration camps.

Following the Japanese attack on Pearl Harbor on December 7, 1941, President Franklin D. Roosevelt issued presidential proclamation 2537 in January of 1942, forcing all non-US citizens from Axis countries to register with the government and to be subject to arrest if found near a military or other secure zone. Under Executive Order 9066, Roosevelt paved the way for the incarceration of over 125,000 people of Japanese ancestry, including many US citizens of second or third generation citizenship. The order was given in February of 1942, against the advice of his advisors, and without the support of the American people. The incarceration of those with Japanese ancestry began in earnest two months after the attack on Pearl Harbor. Of the 125,000 incarcerated in several detention centers across the mainland, between 1,200-1,800 hailed from Hawaii, where martial law kept most of the population under a less restrictive form of confinement. Those arrested were sent first to Sand Island before being shipped to California and dispersed to a mainland concentration camp.