January 14, 1942, President Franklin D. Roosevelt issued Presidential Proclamation No. 2537. This required all Immigrants with Japanese, Italian and German decent to register with the Department of Justice. Certificates of Identification for Aliens of Enemy Nationality were given to those who have completed the registration. The Alien Registration Act of 1940 was the base of the proclamation and more aggressive guidelines were introduced into the law that was to be the first step into a full-scale internment of Japanese Americans on February 1942.
After the Japanese attack on Pearl Harbor on December 7, 1941, the West Coast was deemed vulnerable from Japanese attack. American military analysts were concerned that Japanese Americans living in the western states may perform acts of sabotage on the west-coast defense as well as inflict damage on the agriculture industry.
A federal report in 1941 that was requested by Roosevelt indicated that 90 percent of Japanese Americans were considered loyal to the United States. However, with the mounting pressure from his military advisers, agricultural associations and highly influential California politicians, Roosevelt eventually agreed to the internment of the Japanese American population.
Proclamation No. 2537 was apparently issued in the interest of national security. This in effect permitted the arrest, detention and internment of enemy aliens who will be caught in restricted areas such as ports, water treatment facilities and vital installations as well as areas that are prone to brush fires.
A month after, Executive Order 9066 was reluctantly signed by Roosevelt. The order authorized the Secretary of War to appropriate certain areas as military zones which laid the ground of sending Americans with Japanese, German and Italian descent into internment camps.
There were approximately 120,000 men, women and children of Japanese descent that were evicted from the West Coast and were scattered in different internment camps across the country.
In contrast, not all Japanese Americans in Hawaii were incarcerated nor were they sent in internment camps. Japanese Americans in Hawaii are nearly 40% of the total population of the island. Only a few thousand were detained and investigated by the War Department.
On December 1945, Proclamation 2537 was revoked by Harry Truman with Proclamation 2678.
Eventual findings later on after the war showed that the mass eviction of Japanese Americans at the West Coast was not a result of “military necessity” but was motivated by other reasons. No Japanese American citizen of Japanese national residing in America was ever found guilty of espionage.