Early on 9 December 1981, Philadelphia police officer Daniel Faulkner pulled over a car driven by William Cook, Abu-Jamal's brother. What happened next is in dispute. Shots were fired, and both Officer Faulkner and Abu-Jamal were shot. Faulkner died, and Abu-Jamal was found guilty of his murder in a court case presided over by Judge Albert Sabo, who was widely considered to be a racist. In just one of too many painful examples, a court stenographer said in an affidavit that she heard Sabo say, in the courtroom antechamber, "I'm going to help them fry the n****r."

This latest decision by the court of appeals relates directly to Sabo's conduct of the sentencing phase of Abu-Jamal's court case. The Pennsylvania supreme court is considering separate arguments surrounding whether or not Abu-Jamal received a fair trial at all. What the court of appeals unanimously found this week is that he did not receive a fair sentencing. Philadelphia District Attorney Seth Williams has decided to appeal the decision to the US supreme court, saying:

"The right thing for us to do is to ask the US supreme court to hear this and to make a ruling on it."

As a result of this ruling, Abu-Jamal could get a new, full sentencing hearing, in court, before a jury. In such a hearing, the jury would be given clear instructions on how to decide between applying a sentence of life in prison as opposed to the death penalty - something the court found he did not receive back in 1982. At best, Abu-Jamal would be removed from the cruel confines of solitary confinement on Pennsylvania's death row at SCI Greene. John Payton, director counsel of the NAACP legal defence fund, which is representing Abu-Jamal in court, said:

"This decision marks an important step forward in the struggle to correct the mistakes of an unfortunate chapter in Pennsylvania history ... and helps to relegate the kind of unfairness on which this death sentence rested to the distant past."

His other attorney, Judith Ritter, a law professor at Widener University school of law, told me: "This is extremely significant. It's a life or death decision." I asked her if she had spoken to Abu-Jamal yet, and she told me that the prison failed to approve her request for an emergency legal phone call. I was not surprised, given my many years of covering his case.

He has faced multiple obstacles as he has tried to have his voice heard. On 12 August 1999, as I was hosting Democracy Now!, Abu-Jamal called into our news hour, mid-broadcast, to be interviewed. As he began to speak, a prison guard yanked the phone out of the wall. Abu-Jamal called back a month later and recounted that:

"Another guard appeared at the cell hollering at the top of his lungs, 'This call is terminated!' I immediately called to the sergeant standing by and looking on and said, 'Sergeant, where did this order come from?' He shrugged his shoulders and said: 'I don't know. We just got a call to cut you off.'"

Abu-Jamal sued over the violation of his rights, and won.

Despite his solitary confinement, Abu-Jamal has continued his work as a journalist. His weekly radio commentaries are broadcast from coast to coast. He is the author of six books. He was recently invited to present to a conference on racial imprisonment at Princeton University. He said (through a cellphone held up to a microphone):

"Vast numbers of men, women and juveniles populate the prison industrial complex here in America. As many of you know, the US, with barely 5% of the world's population, imprisons 25% of the world's prisoners and the numbers of imprisoned blacks here rivals and exceeds South Africa's hated apartheid system during its height."

The United States clings to the death penalty, alone in the industrialised world. In fact, it stands with China, Iran, North Korea, Saudi Arabia and Yemen as the world's most frequent executioners. This week's decision in Mumia Abu-Jamal's case stands as one more clear reason why the death penalty should be abolished.

* Denis Moynihan contributed research to this column.