"Steve Earle," he said to the singer/songwriter he had invited to his execution, "I can't believe I had to go through all this just to see you in a suit."
Six months after he watched the man with whom he had corresponded for 12 years die, the Earle is still scarred by the experience. When he plays Cheltenham Town Hall with the Del McCoury Band tonight, "Jonathan's Song" will not be on the set list; the cold cruelty of what Nobles' death certificate described as "Homicide" still overwhelms him.
Earle had been to hell and back before he realised that there were other, worse places to end up in the richest nation on earth. More than two decades of drug addiction had resulted in a 1994 spell in a Tennessee prison, but when film director Tim Robbins sent him a tape of Dead Man Walking, the man responsible for the classic albums, Guitar Town and Copperhead Road, was shaken to the marrow. "Ellis Unit One" was inspired by a scene where a guard says that his role in the death chamber is strapping down the left leg. "They have to compartmentalise it," says Earle, "because the human spirit cannot cope with sole responsible for the taking of human life."
Earle had been a death penalty activist during the Eighties, before drugs took over his life, and that was when he first started writing to Nobles. But after Dead Man Walking he became committed to the cause. He received the letter from Nobles asking if he would witness his execution on 7 October 1998. He agreed, if reluctantly, and on the appointed day found himself watching Jon begin to sing "Silent Night"; the executioner's signal to start the lethal injection.
"When he reached the line `mother and child', all the air went out of his lungs and he gave a shout: `Huh!'" Earle says. "It looked like an invisible cinder block had been dropped on his chest, his head hit his chest so violently that his glasses, a pair of heavy, plastic prison issue glasses, flew off. Five minutes later, he was pronounced dead."
Nobles never pretended to be innocent. He had stabbed two young women to death in their beds and was, in Earle's words, "an escalating serial killer who just happened to get caught first time". But for Earle, the fight for an end to the death penalty is not about guilt or innocence, but about those who have no voice. There are no yuppies on Death Row; 90 per cent of those sentenced to die in the US are literally the poorest of the poor; too destitute to afford expensive legal representation. To spend even a day on the "Journey of Hope" - a two-week tour of Tennessee in the company of relatives of murder victims or Death Row inmates - was, for me, to be convinced beyond doubt that brutality followed by barbarism can never result in healing.
Lois Robison, for example, was refused help for her schizophrenic son because he hadn't shown signs of violence. When he did, he killed five people and is now on Death Row. George White was jailed for life for the murder of his wife, despite the fact that he was shot three times, along with her, in an armed robbery. He was freed after two years and 103 days when an appelate court found his trial to be "a mockery, a sham and a circus."
All "Journey" members have had their lives intrinsically altered by violence, and yet the message behind their campaign last month was one of love and reconciliation. "This death penalty thing is a false promise," White said. "We're promised that, at some point down the road, the taking of another human being's life is going to heal our pain. What a lie."
The most commonly invoked argument is biblical - an eye for an eye - but, campaigners point out, the Old Testament advocates 22 other sins deserving of death, including adultery and working on the Sabbath. In a nation that is big on religion but bigger on denial, 78 innocent people have been sentenced to death since 1977.
On the day that two boys shot 15 of their classmates in Colorado, Earle moved a crowd to tears with "Ellis Unit One". Afterwards, White told them of his own nightmare. "We say that an act of violence should not be followed by an act of vengeance," he said emotionally. "We say, not in our names. Our hearts have bled enough."