At the time of Pearl Harbor, only about 5,000 men of Japanese ancestry were serving in the Army, large numbers of them in the 298th and 299th Infantry Regiments, Hawaii National Guard. Only forty Japanese-American men out of 1,851 were serving in these regiments in the summer of 1940, but after the National Guard was ordered into federal service for one year in September 1940, 3,000 recruits were detailed to these regiments to bring them up to full strength in December 1940, approximately half of whom were Japanese-Americans. After the Japanese attack on Pearl Harbor, the Japanese-Americans in the Army were soon in an unusual limbo at the mercy of their commanders; some "stayed in service, while others were discharged without explanation."
The Hawaii Territorial Guard, authorized since the Hawaii National Guard was in federal service, initially contained many men of Japanese ancestry, but they were disarmed and dismissed in mid-January 1942 after fears arose over their loyalty. These men later petitioned the territorial government to serve, and were attached to the 34th Engineer Regiment as the "Varsity Victory Volunteers," performing manual labor tasks throughout the islands. The Varsity Victory Volunteers were voluntarily disbanded on 31 January 1943, after the announcement of an all-Japanese-American combat team (see below), and many former members went on to join it.
On 5 January 1942, the War Department released an unclear statement regarding enemy aliens; it did not specifically refer to Japanese:
Until arrangements are made by the War Department for the reception of nondeclarant aliens, all nondeclarant aliens and all enemy aliens, both declarant and nondeclarant, will be continued in Class IV-C. A later directive will be issued covering the reclassification of these registrants.
Essentially all draft boards subsequently refused to accept Japanese-American registrants for induction, summarily reclassifying them into classes IV-C (enemy aliens) or IV-F (mentally, morally, or physically unfit for service).
Brigadier General James E. Wharton, the director of the Military Personnel Division of the Services of Supply, recommended in March 1942 that the Japanese-Americans in the Army be "absorbed and dispersed in small numbers throughout the interior of the United States." On 27 March 1942, a War Department recommendation that the acceptance of further Japanese-Americans for military service be suspended was approved. On 30 March 1942, the induction of Japanese-Americans in the Western Defense Command area was prohibited effective 31 March 1942 via a secret telegram to concerned State Directors of Selective Service advising that they would no longer be accepted, to order local boards to discontinue deliveries for such purpose, and to reclassify all Japanese-American registrants into class IV-C.
In mid-1942, the Army initiated an experiment to utilize bilingual first-generation immigrants and foreigners who had intentions of becoming citizens. The 100th Infantry Battalion (Separate), intended to be manned with men of Japanese ancestry, was constituted on 4 June 1942. On 5 June 1942, the Japanese-American men of the 298th and 299th Infantry Regiments were ordered to board transport ships for the mainland under unknown orders. The men arrived at Oakland, California, where the 100th Battalion was activated on 12 June 1942. They later began training as a unit at Camp McCoy, Wisconsin. The 100th Battalion was unique in that it initially was authorized four rifle companies, instead of the three of a normal infantry battalion; the additional company was inactivated in December 1943. After departing the United States in August 1943, the battalion saw heavy fighting in Italy.
Norwegian, Austrian, and Greek battalions were also formed, and a Polish battalion was contemplated, but the experiment saw limited overall success due to the inability of the Army to recruit a sufficient number of men who met their criteria. Only the Norwegian and Japanese battalions saw any substantial service as units.
On 17 June 1942, the War Department prohibited the induction of Japanese-Americans entirely; the only exception was "selected individuals procured for special purposes," i.e. bilingual Japanese-American men for the Military Intelligence Service's Japanese Language School. The Secretary of War advised the Director of Selective Service to "take no action regarding the induction of Japanese Americans" despite what the War Department had said, but on 14 September 1942, the Selective Service System's regulations came into line with the War Department on the question of classification, amending class IV-C to also refer to race or nationality, allowing Japanese-Americans to be officially specifically excluded. By late 1942, the military utility of incarcerated Japanese-Americans was being considered, spearheaded by the Assistant Secretary of War, John J. McCloy, and the evidence of the efforts of the Japanese Language School. The greater issue of the injustice of the incarceration of American citizens was also brought under question:
There were other reasons to link the combat team to the...issue of release from detention. Recruiting...without loosening other restrictions would open the War Department to the charge that the Nisei were being used as "cannon fodder." It would be unfair to deny individuals barred from military service the opportunity to participate...in some other way, and it would be illogical...that loyalty should be tested only for those who might serve in the Army. Discussions began to focus on the combat team as a way to get evacuees out of the camps and to rehabilitate them in the eyes of the public, McCloy's assistant, Colonel Scobey, explained...that the need was "to assist the release of these people from the centers, to expedite the WRA mission."
Initially received as negative due to fears of disloyalty, McCloy's proposals later gained traction, and on 16 December 1942, a recommendation to form a combat unit or units made up of Americans of "Japanese extraction or parentage" was approved in principle by the Army Chief of Staff, General George C. Marshall. On 2 January 1943, the Deputy Chief of Staff, General Joseph T. McNarney, convened a committee to investigate the potential disposition of Japanese-Americans released from internment camps for military service. On 22 January 1943, the War Department constituted the 442nd Regimental Combat Team (RCT), made up of the 442nd Infantry Regiment (less a cannon company and band), the 522nd Field Artillery Battalion (105 mm), the 232nd Engineer Combat Company, and the 206th Army Band.
On 28 January 1943, the War Department announced a quota of 3,000 volunteers from Hawaii and 1,500 from the mainland for the RCT. Men of military age (eighteen to thirty-seven) who wished to volunteer for induction had to fill out and sign the DSS Form 304A, or "Statement of United States Citizen of Japanese Ancestry," more popularly known as the "loyalty questionnaire." The registration teams received a hostile welcome at the internment camps, and questions 27 and 28 were the most contentious, with a significant number of internees answering "no" to one or both questions in either protest or confusion:
27.) Are you willing to serve in the armed forces of the United States on combat duty, wherever ordered?
28.) Will you swear unqualified allegiance to the United States of America and faithfully defend the United States from any and all attack by foreign or domestic forces, and foreswear any form of allegiance to the Japanese Emperor, or any other foreign government, power, or organization?
The results of the surveys were then investigated by War Department intelligence, who determined loyalty or disloyalty. The War Relocation Authority, which had been allowing Japanese-Americans who had demonstrated loyalty to temporarily leave the internment camps for work on farms since the spring of 1942, successfully recommended that the registration process be expanded to all persons over seventeen years old, in order to expedite the ineffective leave program, whose request processing often took months, with the jobs having disappeared in the interim. Issei (first-generation Japanese immigrants) and female Japanese-Americans had to fill out a similar form, the "Application for Leave Clearance."