In the 1948 case United States ex rel. Hirshberg v. Cooke, Commanding Officer, the U.S Supreme Court ruled on a matter concerning military enlistment contracts and involuntary extensions of service. The petitioner, Hirshberg, had enlisted in the Navy Reserve for a period of two years but was held beyond this term under legislation passed by Congress during World War II that allowed for such extensions during national emergencies or war times. He sought release via habeas corpus arguing that his extended detention was unlawful as it violated his enlistment contract which stated he would serve only two years unless voluntarily reenlisted. The court rejected this argument stating that an enlistee's contractual rights are subject to modification by subsequent Congressional legislation due to their subordinate nature compared to legislative power over national defense matters. Therefore, they upheld Congress' right to extend terms of service involuntarily in times of emergency or war without violating any contractual obligations made at time of enlistment.

In the dissenting opinion for United States Ex Rel. Hirshberg v. Cooke, Commanding Officer, Justice Jackson disagreed with the majority's decision to uphold a lower court ruling that denied a writ of habeas corpus to an army enlistee seeking discharge on grounds of minority and parental disapproval. He argued that it was not within the Court's purview to interpret or apply military law in this case as it involved personal rights protected by civil law rather than military jurisdiction or discipline issues. The justice also expressed concern over potential abuse of power by military authorities if they were allowed unchecked discretion in such matters without judicial review. Furthermore, he believed that Congress did not intend for minors who enlisted without parental consent to be held against their will when there is no war emergency present.