In the case of Coleman v. Alabama, the U.S. Supreme Court ruled in 1970 that defendants have a constitutional right to counsel during preliminary hearings under the Sixth Amendment's guarantee of assistance of counsel. The defendant, Coleman, was convicted for robbery and assault with intent to murder by an Alabama court without having legal representation at his preliminary hearing where significant prosecutorial decisions were made. He appealed on grounds that he had been denied his right to counsel as guaranteed by the Constitution. The Supreme Court agreed with him in a 5-4 decision stating that because such proceedings could potentially impact later stages of prosecution, it was necessary for defendants to be represented by lawyers from this stage onwards.

In the dissenting opinion for Coleman v. Alabama, Justice Harlan argued that the majority's decision to extend the right to counsel during preliminary hearings was unnecessary and potentially harmful. He contended that a preliminary hearing is not a critical stage in criminal proceedings where rights could be lost, but rather an administrative step designed to weed out groundless claims before they reach trial. Therefore, he believed it did not warrant constitutional protection under the Sixth Amendment’s guarantee of assistance of counsel. Furthermore, he expressed concern about burdening states with additional costs associated with providing defense attorneys at this early stage in proceedings and warned against federal intrusion into state judicial processes which may disrupt their ability to manage their own systems effectively.