In the 1941 case United States ex rel. Coy v. United States et al., the Supreme Court examined whether a U.S citizen, born in Puerto Rico and residing there, could be drafted into military service under the Selective Training and Service Act of 1940. The plaintiff argued that as a resident of Puerto Rico - an unincorporated territory not considered part of the United States for constitutional purposes - he was exempt from conscription laws applicable to citizens living within U.S borders. However, the court ruled against him stating that while certain constitutional protections may not extend to unincorporated territories like Puerto Rico, citizenship did confer obligations such as military service regardless of residence location.

In the dissenting opinion for UNITED STATES ex rel. COY v. UNITED STATES et al., 1941, it was argued that Coy's conviction should be overturned because his constitutional rights were violated when he was not allowed to cross-examine witnesses against him during his court-martial trial. The dissenting justices believed that this denial of a fundamental right under the Sixth Amendment rendered the entire proceedings invalid and unjust, regardless of whether or not there may have been sufficient evidence to convict him otherwise. They contended that every accused person has an absolute right to confront their accusers in order to challenge their credibility and truthfulness, which is a critical aspect of ensuring fair trials and preventing wrongful convictions.