Participants in criminal justice systems have a constitutional right under the Sixth Amendment to “the assistance of counsel” at trial; the right to legal representation is also protected, and applicable to the states, by the Due Process Clause of the Fifth and Fourteenth Amendments. This right is zealously protected; failure to respect it may invalidate critical criminal procedures.

As a practical matter, the right to counsel may mean three similar and linked but nonetheless somewhat different things: (1) the right to insist that an attorney be present; (2) the right to be informed that one has a right to an attorney before proceeding; and (3) the right to have an attorney—whether privately retained or appointed to represent an indigent who cannot afford one—actually present before the case can proceed. With respect to (1), other than in the grand jury itself, anyone—even if not arrested or at apparent risk of being accused, such as a witness or even a victim—may wish to be accompanied by an attorney of her choice for advice or support, and generally has a right to do so in that the police or investigator cannot ask that the attorney be excluded.