Mendoza (P) was a Filipino national residing in the U.S. P petitioned for citizenship in 1978 based on a statute that granted foreigners who served honorably in the U.S. military during WWII the right to apply for and receive U.S. citizenship. The act was repealed after the war, and only applicants who had applied for citizenship prior to 12-31-46 were entitled to naturalization. The U.S. immigration office in the Philippines was closed from October 1945 until August 1946. P argued that this fact excused his delay. P also relied upon a 1975 decision in district court for 68 Filipino war veterans. The District Court held that under the doctrine of nonmutual offensive collateral estoppel the Government could not relitigate the due process issue, because that issue had already been decided against the Government. The Court of Appeals concluded that the District Court had not abused its discretion in applying that doctrine against the United States in this case. The Supreme Court granted certiorari.