In Moore v. Duckworth, the U.S Supreme Court ruled in favor of respondent Duckworth, a warden at Indiana State Prison. The petitioner, Moore was convicted for armed robbery and claimed that his Fifth Amendment rights were violated because he did not have an attorney present during police interrogation where he made incriminating statements which were later used against him in court. He also alleged that his Sixth Amendment right to counsel was violated when the trial judge denied his request for a continuance so he could secure another lawyer after falling out with his original one just before trial began. However, the Supreme Court found no constitutional violation as it held that Miranda warnings given to Moore by police officers sufficiently apprised him of his rights under law despite some minor deviations from standard language; and regarding denial of continuance request, it concluded there had been no abuse of discretion since there wasn't any clear evidence showing prejudice towards defendant due to this decision.

In the dissenting opinion for Moore v. Duckworth, Justice Thurgood Marshall argued that the majority's decision was a departure from established precedent regarding confessions obtained through police coercion. He contended that Moore's confession should have been deemed inadmissible because it was extracted under duress and without proper Miranda warnings being given by law enforcement officers. Furthermore, he disagreed with the majority’s view on harmless error doctrine application to this case, believing instead that such an erroneous admission of a coerced confession could not be considered harmless beyond reasonable doubt as it directly influenced jury’s verdict against Moore. The justice also criticized Indiana courts' handling of this case and their failure to properly assess whether or not there had been constitutional violations during interrogation process which led to obtaining incriminating statements from defendant.