In the 1942 case Ex parte Kumezo Kawato, the U.S. Supreme Court ruled that an enemy alien during wartime does not lose his right to sue in federal court unless Congress specifically suspends that right. The case involved Kumezo Kawato, a Japanese national living in Seattle who was declared an enemy alien after Japan's attack on Pearl Harbor. Despite this status, he filed a lawsuit against another individual over a business dispute. The lower courts dismissed his suit based on his status as an enemy alien but the Supreme Court overturned these decisions and allowed him to proceed with his lawsuit.

In the dissenting opinion for Ex parte Kumezo Kawato, it was argued that the majority's decision to deny citizenship rights based on wartime circumstances set a dangerous precedent. The dissent emphasized that an individual’s right to pursue naturalization should not be affected by their country of origin being at war with the United States. It was further pointed out that Mr. Kawato had demonstrated his loyalty and commitment to America through years of residence and compliance with all legal requirements for naturalization, which should have been considered in his favor. The dissent also criticized the majority's interpretation of existing laws as overly broad and potentially harmful towards immigrants seeking U.S citizenship during times of international conflict.