Anthony Porter spent 16 years on death row and was 50 hours away from execution by lethal injection when another man confessed to the murders for which he was falsely convicted. Two days later he walked free from his prison in Chicago, Illinois. "Them crooked cops framed me," he said. "They didn't care nothing for the truth. It hurt me so much. My life is torn apart." That was in February 1999.

On January 31 this year, Republican governor George Ryan declared a moratorium on executions in the state of Illinois. Previously an enthusiast for death by lethal injection, he was won over by the Porter case and others like it. Illinois, said Ryan, had a "shameful record of convicting innocent people". Since the death penalty was reintroduced in the state in 1977, 13 inmates on death row have been proved innocent - more than have been executed.

Ryan's decision opened a floodgate. 15 of 38 US states with the death penalty announced that they would review their policies. On February 11, the justice department launched an investigation into whether capital punishment is inflicted disproportionately on black people. On the same day, Senator Patrick Leahy introduced a bill designed to improve defendants' chances of proving their innocence. "America," editorialized the New York Times, "is at last beginning to grapple honestly with the profound flaws of the death penalty system."

Porter owes his freedom to an undergraduate journalism class in Chicago. As a class project, students at Northwestern university's Medill school of journalism re-examined his conviction. Visiting the scene of the crime, they found that a key "eye-witness" couldn't possibly have seen what he claimed to have seen: there was a fence in the way. When confronted, the witness promptly admitted that the police had "threatened, harassed and intimidated" him into falsely identifying Porter. But the students didn't stop there. They tracked down the real killer and got him to confess.

So far, the US debate is not about the morality of capital punishment, but about executing the innocent. Since 1976, when the Supreme Court reinstated capital punishment, 81 convicts on death row have been found innocent and released - some, like Porter, just hours away from being killed. It is highly probable that some of the 612 people executed during the same period were also innocent.

For the World Alliance of Reformed Churches, capital punishment itself is the issue. The 22nd general council (Seoul 1989) expressed "deep concern about the increasing use of the death penalty for political actions, capital crimes such as murder, and other violations of the social order as presently determined by legitimate and illegitimate governments... We are convinced that the death penalty should be universally abolished."

This conviction was grounded in a theological understanding of the justice of God "which demands that the inherent worth of every human life be accorded dignity, not contingent on the moral rectitude of human beings". The council said that "any action that diminishes the value of human life is abhorrent to WARC and its member churches."

Amnesty International's US Director, Dr William Schultz, puts it more simply: "just as we don't steal from the thief or rape the rapist - we ought not to kill the killer".

Páraic Réamonn