WASHINGTON - Criminal defendants have a constitutional right to effective lawyers during plea negotiations, the Supreme Court ruled on Wednesday in a pair of 5-to-4 decisions.
Because about 95 percent of criminal convictions arise from guilty pleas, the decisions represent a vast expansion of judicial supervision of the criminal justice system.
"Criminal justice today is for the most part a system of pleas, not a system of trials," Justice Anthony M. Kennedy wrote for the majority. "The right to adequate assistance of counsel cannot be defined or enforced without taking account of the central role plea bargaining takes in securing convictions and determining sentences."
Justice Antonin Scalia took the unusual step of summarizing his dissents from the bench. "Today's opinions open a whole new field of constitutionalized criminal procedure: federal plea-bargaining law," he said.
Scholars who welcomed that development agreed about its significance.
"The Supreme Court's decision in these two cases constitute the single greatest revolution in the criminal justice process since Gideon v. Wainwright provided indigents the right to counsel," said Wesley M. Oliver, a law professor at Widener University.
It has long been established that defendants are entitled to new trials if they can show that incompetent work by their lawyers probably affected the verdicts in their cases. The Supreme Court has also required lawyers to offer competent advice in urging defendants to give up their right to a trial by accepting a guilty plea.
The cases decided Wednesday answered a harder question: What is to be done in cases in which a lawyer's incompetence caused the client to reject a favorable plea bargain?
Justice Kennedy, who wrote both majority opinions and was joined both times by the court's four more liberal members, acknowledged that allowing the possibility of reopening cases involving rejected pleas that were followed by convictions presented all sorts of knotty problems. But he said the realities of American criminal justice required the court to take action.
One of the cases, Missouri v. Frye, No 10-444, involved Galin E. Frye, who was charged with driving without a license in 2007. A prosecutor offered to let him plead guilty in exchange for a 90-day sentence.
But Mr. Frye's lawyer at the time, Michael Coles, failed to tell his client about the offer. After it expired, Mr. Frye pleaded guilty without a deal in place, and a judge sentenced him to three years.
The second case, Lafler v. Cooper, No. 10-209, concerned Anthony Cooper, who shot a woman in Detroit in 2003 and then received bad legal advice. Because all four of his bullets struck the victim below her waist, his lawyer said, Mr. Cooper could not be convicted of assault with intent to murder.
Based on that advice, Mr. Cooper rejected a plea bargain that called for a sentence of four to seven years. He was convicted, and is serving 15 to 30 years.