The execution of Troy Davis in Georgia this week and the questions it raised among proponents as well as opponents of the death penalty are likely to have lasting repercussions in the nation’s debate over capital punishment.

Davis, who was put to death by lethal injection Wednesday night, had become a cause celebre for critics who said the case exposed flaws in the justice system that could lead to the execution of an innocent person. Many of those critics, including Amnesty International and the NAACP, pledged Thursday to redouble their efforts to abolish the death penalty.

Some of those who backed clemency for Davis said that although they were not certain that he was innocent of his crimes, his case deserved more court review because of doubts about witness testimony. At the very least, they said, those doubts should have disqualified Davis from being put to death.

Davis, 42, was convicted of the 1989 killing of an off-duty police officer in the parking lot of a Savannah Burger King. In court, seven witnesses said they saw Davis shoot Officer Mark MacPhail, who had been trying to break up a dispute, and two more said Davis confessed to them. Years later, all but two of the eyewitnesses recanted.

As the case moved through the court system over the past two decades, including three trips to the U.S. Supreme Court, prosecutors and others convinced of Davis’s guilt were less vocal than his supporters. But this week, Spencer Lawton, the former Chatham County prosecutor who handled the case, said some Davis supporters were ignoring all the facts.

“There are people who have not troubled themselves to acquaint themselves with the record,” Lawton told CNN on Tuesday, “who don’t know the facts, who do oppose the death penalty and who have been willing, on the strength of that emotion alone, to assume the truth of the allegations of the weakness of evidence in the case.”

Davis became a marquee case, not just for death penalty opponents but also for some supporters, including former congressman Robert L. Barr Jr. (R-Ga.) and former FBI director William S. Sessions, who served during the Reagan and George H.W. Bush administrations. They said prisoners should not be put to death if there is any question of guilt.

“I support capital punishment,” Barr wrote in an April letter to the Georgia State Board of Pardons and Paroles. “However, my support of the death penalty hinges on assurances of fundamental fairness and accuracy in the justice system leading up to executions. In the case of Troy Anthony Davis, the system has not provided the requisite assurances.”

Davis’s execution was stayed in 2008, and the next year, the Supreme Court ordered a federal judge to reconsider the case. U.S. District Judge William T. Moore ruled in a 176-page opinion last year that there wasn’t clear and convincing evidence that a jury would have come to a different conclusion based on the new information, which he called “smoke and mirrors.”

Although the case relied heavily on the testimony of eyewitnesses, prosecutors also cited a shell casing found at the scene that matched one recovered near another shooting that police say Davis committed.

Moore’s ruling further frustrated Davis’s supporters.

“It’s hard to get any consensus on anything in this country, but . . . you can get a lot of consensus on the idea that if there is some real doubt about someone’s guilt, that’s not a case where you should use the death penalty,” said George Kendall, a former attorney for the ACLU who has worked pro bono on a number of death penalty cases.

The case coincides with stepped-up debate about the reliability of eyewitness testimony. According to the Innocence Project, which seeks to exonerate wrongly convicted prisoners, eyewitness misidentification plays a role in more than 75 percent of convictions that are overturned through DNA testing.

The Supreme Court’s decision not to review Davis’s case again came Wednesday night in an order that followed the court’s familiar one-sentence manner: “The application for stay of execution of sentence of death presented to Justice Thomas and by him referred to the Court is denied.”

Cases go to the justice responsible for the part of the country involved — in this case, Justice Clarence Thomas — and are referred to the entire court. It takes a majority of the court to issue a stay. The court has issued two in the past week, both in cases from Texas.

Sometimes, when a stay is denied, a justice notes that he or she would have granted a stay or writes a dissent to the decision. No such objection was noted in Davis’s case.

Staff writer Bob Barnes and staff researcher Madonna Lebling contributed to this report.