The United States did not handle the issue of possible spying and sabotage diplomatically, and in turn, caused many damages to the Japanese people's lives. If the United States looked at the Munson Report, and how loyal the Japanese were with their cooperation signing the loyalty oath, the U.S. should have made the diplomatically sound decision to not intern the Japanese.

Munson Report

The Munson Report was a 25 page report written by Curtis Manson (a Chicago businessman) determining the loyalty of the Japanese people in Hawaii and the Pacific West coast. Munson toured Hawaii and the West coast to observe the Japanese and talk to military intelligence officers to get their statement on how loyal the Japanese were. The Report was submitted to the White House on November 7, 1941, one month before Pearl Harbor was attacked. (Densho) It stated that there was no problem with the Japanese living in Hawaii and on the West Coast and that they were rated to be 90-95% loyal to United States. (Weglyn pg. 106)
The Munson Report

Loyalty Oath

The Loyalty Oath was an option given to the able bodied Japanese internees that were of military age (17-45.)  The "Oath" consisted of two questions on a questionnaire given to these Japanese internees. The questions were 27, "Are you willing to serve in the armed forces of the United States on combat duty, whenever ordered?" and question 28, "Will you swear unqualified allegiance to the United States of America and faithfully defend the United States from any or all attack by foreign or domestic forces, and forswear any form of allegiance or obedience to the Japanese emperor, or any other foreign government, power, or organization?" (Densho) If you answered "yes" to both questions, you were then enlisted in the military and celebrated as an activist for Japanese freedom. If you answered "no" to both, then you were sent to one of the worst camps, and looked down upon in the Japanese community. The immense amount of people that answered "yes" to the oath was a testament to the loyalty that the Japanese had to the United States. Not only did an large number of people sign the oath and go to war for the United States, but the 442nd Infantry, an all Japanese battalion, went on to be the most decorated regimen in United States history. (Weglyn)
The Loyalty Oath