Just before he was put to death in 1992, Roger Coleman read a statement.

“An innocent man is going to be murdered tonight,” he said. “When my innocence is proven, I hope Americans will realize the injustice of the death penalty as all other civilized countries have.”

Then a switch was thrown, the room filled with the thunder of electric current, and Coleman’s body was thrown against the restraining belts of the chair. Minutes later, he was pronounced dead, executed for the 1981 rape and murder of a young Virginia woman named Wanda McCoy.

Coleman always said he did not do it. And, as detailed in “May God Have Mercy,” John Tucker’s unsparing and unsentimental account of the crime and its aftermath, there is ample reason to suspect that he did not. Including a timeline, supported by a witness and physical evidence, that would have made it difficult, if not impossible, for him to have been where prosecutors said he was and to have done what they said he did.

But Coleman’s court-appointed attorneys were inexperienced and consequently, inept. So they didn’t bring this out at trial. Didn’t hammer inconsistencies in the police reports. Didn’t challenge holes in the state’s theories. Didn’t question questionable testimony from key prosecution witnesses.

So Coleman was sentenced to death. Despite pleas from Pope John Paul II and Mother Teresa, despite court appeals and a request for clemency, despite a growing sense among a growing number of observers that he had not committed the crime.

It is now possible, thanks to advances in DNA technology, to determine Coleman’s guilt or innocence to a statistical certainty. Possible to know the truth. If we have the guts.

Virginia, it seems, does not. Several newspapers and an anti-death penalty organization have sought for years to have the new test done — at their own expense. Virginia officials resisted all the way to the state Supreme Court, which, in 2002, ruled in their favor. Last month, the request went to Gov. Mark Warner who is, at this writing, still considering it.

One wonders what there is to consider.

If the state is confident that it executed the right man, it should welcome the chance to prove it and in the process, deal a humiliating setback to opponents of capital punishment.

And if Virginia did, indeed, kill an innocent man, that is something we all need and deserve to know. Not least because it means Wanda McCoy’s killer got away.

Therein, of course, lies the rub. The state cannot allow itself to say, “Oops.” Because faith in the death penalty is rooted in the fiction of perfection, the lie that says we make no mistakes, allow no biases, when we impose this ultimate and irrevocable sanction. Death penalty advocates are party to an unwritten pact requiring them to believe what is demonstrably untrue.

So what do they do when they receive information proving that untruth, information that leads them where they don’t wish to go? All too frequently, they just look the other way.

This is what has happened to studies indicating that race, gender, geography and poverty help determine who gets executed. It’s what has happened to news stories about dozens of death row inmates who went free after their innocence was proved.

But Roger Coleman is a different matter. How could anyone look the other way if it was revealed that Virginia executed an innocent man? How could we do anything except finally face the immorality, unfairness and arbitrariness of capital punishment. And finally admit that it is simply wrong.

In 1984, Coleman was offered the chance to join what was ultimately a successful escape attempt. He declined because, he said, he was innocent and believed his lawyers would be able to make a court see that. To make the system work.

It never happened, but to his dying day, Coleman retained his faith that the truth would someday be known. Now it can be.

Apparently, that’s what Virginia is afraid of.

Leonard Pitts Jr. is a columnist for the Miami Herald. His via e-mail address is: lpitts@herald.com.