Prior to Pearl Harbor 3,500 Nisei had been drafted into the U.S. Army. Following Pearl Harbor some were discharged, and men of draft age were classified as aliens.
Nisei leaders felt it was essential for their future that their young men be permitted to serve in the armed forces. As a result the 442nd Regimental Combat Team was formed, made up almost entirely of Japanese Americans. When the call for volunteers for the 100th Infantry Battalion went out in Hawaii, the response was overwhelming. Understandably, the response was less enthusiastic behind the barbed wire of the mainland camps. Many young men resisted at first, but eventually 1500 Nisei joined men of the 100th Battalion from Hawaii to form the 442nd Combat Team.
The unit was sent to the European Theater where in seven campaigns they suffered casualties amounting to triple their original strength. The team was composed of 18,400 Japanese Americans, half of whom came from internment camps. It was the most decorated unit of World War II. Its members received 52 Distinguished Service Crosses, 560 Silver Stars, 4,000 Bronze Stars, 9,486 Purple Hearts, Seven Presidential Distinguished Unit Citations and one Medal of Honor.
The role of Japanese Americans as linguists in the Pacific war was a well-kept military secret for a long time. The men in the Military Intelligence Service (MIS) served as the eyes and ears of the Allied fighting forces throughout the Pacific Theater, often at great risk of being mistaken for the enemy.
By obtaining crucial military intelligence the Japanese American soldiers were credited with having saved countless lives and shortening the Pacific war by two years. In all 33,000 Nisei served in the armed forces in World War II the highest percentage in proportion to the total population of any American ethnic group.