In Stewart v. Massachusetts, the U.S. Supreme Court ruled in 1971 that a state's decision to retry a defendant after his initial conviction was overturned did not violate the Double Jeopardy Clause of the Fifth Amendment. The case involved Robert Stewart, who had been convicted for armed robbery in Massachusetts but had his conviction reversed on appeal due to an error made by the trial judge during jury instructions. Upon retrial, he was again convicted and appealed this second verdict arguing it violated his constitutional protection against double jeopardy - being tried twice for the same crime. However, the Supreme Court upheld his second conviction stating that since there were errors in his first trial which led to its reversal on appeal; therefore, it could not be considered as 'jeopardy' under legal terms and hence does not prevent re-prosecution.

In the dissenting opinion for Stewart v. Massachusetts, it was argued that the case should have been dismissed due to mootness. The dissenting justices believed that since petitioner's sentence had already been reduced by a state court and he had been released from custody, there was no longer an actual controversy at stake in this case. They also disagreed with the majority's decision to remand the case back to lower courts for further proceedings on whether or not petitioner received effective assistance of counsel during his trial. According to them, such action would only prolong unnecessary litigation without providing any meaningful relief for petitioner who has already served his time in prison.