Japanese-American Claims Act
The attack on Pearl Harbor was a surprise military strike by the Imperial Japanese Navy on the United States naval base at Pearl Harbor in Honolulu, Hawaii, on the morning of December 7, 1941. The attack sank four U.S. battleships, destroyed 188 U.S. aircraft, and killed 2,403 U.S. citizens within two hours, and led to the United States joining World War II. Once the United States entered the war and anti-Japanese sentiment began to circulate, Americans increasingly reacted with racism and hostility, viewing people of Japanese descent were treated as enemies regardless of whether they were U.S. citizens. The U.S. government expressed concerns about the loyalty of the Japanese people living in America and about Japanese spies sending information to Japan. "The U.S. Department of the Treasury froze the assets of all citizens and resident aliens who were born in Japan, and the Department of Justice arrested some 1,500 religious and community leaders as potentially dangerous enemy aliens. Because many of the largest populations of Japanese Americans were in close proximity to vital war assets along the Pacific coast. The result was President Franklin D. Roosevelt's Executive Order 9066."
Pearl Harbor
Following the overthrow of the Hawaiian Kingdom, the United States Navy established a base on the island in 1899. On December 7, 1941, the base was attacked by the Imperial Japanese Navy airplanes and midget submarines, causing the American entry into World War II. One of the main reasons that Pearl Harbor happened was because the United States had major communication breakdowns among several branches of the U.S. armed services and departments of the U.S. government. This led to the surprise Japanese attack at the Hawaiian air base. There was no meaningful plan for the air defense of Hawaii, for American commanders had no understanding of the capabilities and proper employment of air power. As it was, had the Pacific Fleet acted on the war warnings it undoubtedly would have sortied and been at sea on December 7, where the major ships would have been sunk in deep water, making salvage impossible. 
Shortly after the devastating Japanese surprise attack at Pearl Harbor two American military commanders, Lt. Gen. Walter Short and Adm. Husband Kimmel were demoted of their full ranks. The two American commanders later sought to restore their reputations and full ranks.