By affording a right to assistance of counsel, the Founders specifically meant to reject the English practice of prohibiting felony defendants from appearing through counsel except upon debatable points of law that arose during trial. After the Glorious Revolution in England (1688), Parliament passed a statute allowing those accused of treason to appear through counsel. The Framers clearly meant to extend the right to be heard through counsel to cases of felony as well as treason.

History does not speak so clearly to the related but distinct question of whether a defendant who is too poor to retain private counsel should have a right to a lawyer paid at public expense. Self-representation appears to have been common at the time of the Founding, but representation by professional lawyers became more frequent during the first half of the nineteenth century. Some of the nineteenth-century treatise writers assumed that the legal profession would offer voluntary legal assistance to indigent defendants in serious cases. There were some instances of litigation over the question of whether volunteer lawyers for the poor would have an action for fees against the public authorities. The common practice thus seems to have been that members of the bar would represent indigent criminal defendants, motivated by public spirit, a thirst for trial experience, or the attendant publicity. In some places such lawyers were compensated at public expense.

While there can be no doubt that the Framers valued the right to counsel, their primary purpose lay in removing legal obstacles to representation by lawyers privately retained by defendants who could afford lawyers. Not until 1938 did the Supreme Court hold that the Sixth Amendment required court-appointed counsel for defendants too poor to afford private counsel, or a knowing and intelligent waiver of court-appointed counsel by the accused. Johnson v. Zerbst (1938). The Sixth Amendment, however, applied only in federal cases. As late as 1963, several poorer states, all in the South, refused to provide appointed counsel for all indigent felony defendants, many, if not most, of whom were black. Prior to 1963, the Supreme Court had addressed the question of counsel for the indigent accused persons in state cases under the Due Process Clause of the Fourteenth Amendment, rather than under the Sixth Amendment, which deals specifically with the right to counsel. In the state cases, beginning with Powell v. Alabama (1932), the Court read due process to require appointed counsel in capital cases, and in felony cases when they presented special needs for legal advice.

The modern law interpreting the Right to Counsel Clause really begins with the 1963 decision in Gideon v. Wainwright, holding that the Fourteenth Amendment incorporates Sixth Amendment’s guarantee of the right to counsel, making it applicable in state as well as federal cases. Gideon left open at least three important questions: First, when does the right to counsel arise? Second, are there offenses so minor that the government need not provide appointed counsel? Third, how competently must defense counsel perform to satisfy constitutional standards?

In the years since Gideon, the Court has held that the right to counsel arises with the institution of formal proceedings by way of indictment, information, complaint, or arraignment. 

Thus, whatever rights to counsel a suspect enjoys after arrest but before the filing of the charge (a timing decision largely within the control of the authorities) come not from the Sixth Amendment but from other sources, such as the Miranda rights derived from the Fifth Amendment Self-Incrimination Clause. Once the Sixth Amendment right to counsel has attached, the accused has the right to the presence of counsel during all subsequent critical stages of the case, including the preliminary hearing, pretrial motions, interrogation, plea negotiations, and of course the trial itself. The right to counsel ends with a final judgment of the trial court. The Supreme Court has declared that the right to counsel on appeal arises from the Equal Protection Clause, not the Sixth Amendment.

As to the level of criminal charge that triggers the right to counsel, the courts have never complied with the literal meaning of the Sixth Amendment. In this instance, at least, “all” does not mean “all criminal prosecutions”; it means some. Petty offenses have been adjudicated without counsel from the time of the Founding to this day. The traditional understanding of petty offenses included misdemeanors punishable by less than six months in jail. The modern Supreme Court has held that no offense can be deemed petty for purposes of the exception to the right to counsel if the accused does in fact receive a sentence that includes incarceration, however brief.

As for the standard of representation, the Supreme Court in Strickland v. Washington (1984) adopted a two-step test for ineffective assistance of counsel claims. To set aside a plea, verdict, or sentence on account of defective lawyering, the defendant must show that defense counsel’s performance fell outside the range of professional competence and that counsel’s performance prejudiced the defendant so as to call the reliability of the proceedings into question. In the first prong of the test, the courts indulge a presumption of competence; many vital decisions (e.g., whether to accept a plea bargain, whether to call the defendant as a witness) are so problematic that they are classified as unreviewable tactical choices. In the second prong, the burden lies on the defendant to show that, but for counsel’s unprofessional errors, there is a fair probability that the results of the proceedings might have been different. Prejudice against the right to effective assistance of counsel is presumed only from the actual or constructive denial of counsel, an actual conflict of interest that impairs counsel’s performance, or arbitrary interference by court ruling or statute with counsel’s presentation of the defense. Lack of sufficient resources for indigent defense, in and of itself, does not constitute a violation of the Sixth Amendment. That question is left to Congress and the state legislatures to address.

Recent cases suggest the Court is looking more closely at the performance of counsel for the great majority of defendants whose convictions result from pleas. Under these cases, a guilty plea may be vacated when defense counsel fails to advise the client of adverse immigration consequences, or fails to communicate to the defendant a prosecution offer. A trial conviction may be set aside if counsel gave negligent advice that exaggerates the defendant’s chances at trial.