In the 1942 case of Yasui v. United States, Minoru Yasui, a Japanese-American lawyer from Oregon, challenged the constitutionality of curfews imposed on individuals of Japanese descent during World War II. The U.S military had issued orders restricting the movement and activities of people with Japanese ancestry following Japan's attack on Pearl Harbor in December 1941. Yasui deliberately violated this order to test its legality and was subsequently arrested and convicted by a lower court. Upon appeal to the Supreme Court, his conviction was upheld with unanimous decision stating that in times of war, certain restrictions may be placed upon civil liberties for national security purposes if there is reasonable ground to believe that such action is necessary for public safety against espionage or sabotage. However, it did not rule specifically on racial discrimination aspect but rather focused solely on issues related to wartime necessity.

In the dissenting opinion for Yasui v. United States, Justice Murphy argued that the curfew order violated constitutional rights and was based on racial discrimination rather than military necessity. He contended that there was no substantial evidence to justify such a drastic measure against all persons of Japanese ancestry, including American citizens like Yasui. Furthermore, he believed it was unconstitutional to criminalize an entire group's daily activities without clear proof of their disloyalty or potential threat to national security. In his view, this case represented a dangerous precedent where civil liberties could be suspended under the guise of wartime exigencies. Thus, he disagreed with the majority's decision upholding Yasui's conviction for violating a racially discriminatory curfew order during World War II.