In the case of Reid v. Covert, 1956, the U.S. Supreme Court ruled that American civilians abroad are protected by the Constitution and cannot be tried by military tribunals, overturning previous rulings in two lower courts. The case involved Clarice Covert who had been convicted for murdering her husband at an airbase in England where he was stationed as a member of United States Air Force. She was initially tried and convicted without a jury under court-martial proceedings according to an agreement between US and UK (Status of Forces Agreement). However, upon appeal to the Supreme Court it held that such trials were unconstitutional because they violated Fifth Amendment rights which state no person shall be deprived life or liberty without due process of law; Sixth Amendment right guaranteeing trial by jury; Article III Section 2 Clause 3 requiring criminal trials to occur in states where crimes have been committed unless otherwise stipulated by Congress.

In the dissenting opinion for Reid v. Covert, Justice Harlan argued that the majority's decision to extend constitutional protections to U.S. citizens abroad was misguided and inconsistent with historical precedent. He contended that while American citizens should be protected by their rights domestically, it is not practical or feasible to apply these same standards in foreign jurisdictions where different legal systems are in place. Furthermore, he believed this ruling could potentially interfere with military operations overseas and undermine national security interests. In his view, the Constitution did not necessarily follow the flag; rather its application depended on a variety of factors including territorial location and political considerations.