THE Supreme Court ruled correctly on Monday when it found that Georgia prosecutors in Foster v. Chatman had illegally barred African-Americans from serving as jurors in a death penalty trial. But the decision does not end racial discrimination in jury selection. The best way to do that is to limit the number of jurors that lawyers can strike for no reason at all to just one or two per side.

Both prosecutors and defense lawyers can exclude any number of prospective jurors for legitimate reasons — if a juror knows the defendant, has formed an opinion about the case or is unlikely to be impartial. But lawyers can also dismiss several more potential jurors simply because they do not want them — without explaining why. In federal felony trials, the prosecutor has six peremptory challenges and the defense usually has 10. In federal death penalty cases, each side has 20. State numbers vary.

In the Foster case, which dates from the 1980s, the prosecutors eliminated people simply because of race. Timothy Foster, a black man, stood accused of killing an elderly white woman when he was a teenager. The prosecutors worked conscientiously to exclude the potential black jurors; they marked their names with a “B” and highlighted each black juror’s name in green on four different copies of the juror list. Those jurors were ranked against one another in case, one member of the prosecutorial team said, “it comes down to having to pick one of the black jurors.” The plan worked, and an all-white jury sentenced Mr. Foster to death.