What was the main argument used in the Korematsu v. United States?

Korematsu's main argument stemmed from his belief that Executive Order 9066 was in violation of the Fifth Amendment and was unconstitutional. The order itself, was issued by then president, Franklin D. Roosevelt, authorized the military to exclude people from certain areas due to security. As a result, the order was responsible for the relocation and internment of Japanese Americans during WWII.