Abu-Jamal, a former Black Panther, has spent nearly 30 years on death row after his 1982 conviction for killing white officer Daniel Faulkner.
A federal appeals court this year upheld his conviction, but agreed the death-penalty instructions were potentially misleading and ordered a new sentencing hearing.
City prosecutors appealed that order, but must now decide whether to pursue the death penalty for a second time. Only three people have been executed in Pennsylvania since 1976, and none since 1999.
The officer's widow, Maureen Faulkner, had supported the city's appeal, but wondered Tuesday whether it was time to end the long-running drama. A re-hearing would cost the city millions, and keep Abu-Jamal in the media spotlight, she said. And many of the relevant witnesses are dead.
"He does get in the spotlight, and you just don't know which way it's going to go," the 54-year-old Faulkner said from her home in southern California. "I have to think of the city of Philadelphia and the costs it would incur to open a new hearing. Any logical person would, after 30 years."
Abu-Jamal's writings and radio broadcasts from death row have made him a cause celebre and the subject of numerous books, movies and death-penalty protests. Other books, one by Maureen Faulkner, have supported her point of view.
Prosecutors plan to take some time before deciding their next move, District Attorney Seth Williams said in a statement.
Widener University law professor Judith Ritter and the NAACP Legal Defense & Educational Fund represented Abu-Jamal in the latest appeal.
"At long last, the profoundly troubling prospect of Mr. Abu-Jamal facing an execution that was produced by an unfair and unreliable penalty phase has been eliminated," said John Payton, president of the fund. "Our system should never condone an execution that stems from a trial in which the jury was improperly instructed on the law."
According to trial testimony, Abu-Jamal saw his brother scuffle with the 25-year-old patrolman during a 4 a.m. traffic stop in 1981 and ran toward the scene. Police found Abu-Jamal wounded by a round from Faulkner's gun. Faulkner, shot several times, was killed. A .38-caliber revolver registered to Abu-Jamal was found at the scene with five spent shell casings.
Tuesday's decision upholds a 2001 ruling by U.S. District Judge William H. Yohn Jr., who first ruled that Abu-Jamal deserved a new sentencing hearing because of flawed jury instructions on aggravating and mitigating factors.
Philadelphia prosecutors fought the decision, but the 3rd U.S. Circuit Court of Appeals ruled against them in 2008.
The U.S. Supreme Court heard an Ohio case involving similar sentencing issues last year, but rejected the inmate's claim - and ordered the 3rd Circuit to revisit its Abu-Jamal decision.
However, the Philadelphia-based court stood its ground in April, insisting the two cases were different.
Under Pennsylvania law, Abu-Jamal should have received a life sentence if a single juror found the mitigating circumstances outweighed the aggravating factors in Faulkner's slaying. The 3rd Circuit found the verdict form confusing, given its repeated use of the word "unanimous," even in the section on mitigating circumstances.
Williams has conceded that courts in Philadelphia and the U.S. "have had a history of problems and racism," while adding of the Faulkner case, "This is not a whodunit."
Abu-Jamal, a radio journalist and cab driver born Wesley Cook, is now 57.
Maureen Faulkner wants him mixed into the general prison population if she and prosecutors agree to a term of life without parole. She believes he now has an enviable setup as a world-famous inmate, with access to a law library and computer.
"I think he's got his nice little cottage industry going from prison," she said. "He lives each and every day like he's going to work."