Prison reform advocates are making a final attempt to rally support for Troy Davis, a Georgia prisoner who soon expects to face his fourth execution date. Davis has been on death row for two decades for the 1989 murder of Savannah police officer Mark MacPhail, despite substantial evidence seriously calling his guilt into question. Now the NAACP, Color of Change, and Amnesty International are rallying their members around the case.

There is no physical evidence linking Davis to the crime, and since his conviction, seven out of nine witnesses have recanted their testimonies, many of them claiming that their affidavits were coerced or made under intense pressure by police. Furthermore, several new witnesses have emerged identifying another man, an eyewitness who implicated Davis in the crime and had a gun the night of the murder, as the culprit.

Over the years, Davis and his lawyers have exhausted avenues to prove his innocence. The court system has refused to grant him a new jury trial and has rejected new evidence his attorneys presented at federal hearings. Since 2007, three execution dates were delayed within hours or days. Most recently, the U.S. Supreme Court denied Davis’ final appeal on March 28, leaving the coast clear for Georgia to set a new execution date as early as next month.

"If the presumption of innocence means anything in our justice system, we cannot execute a man with such an overwhelming body of evidence pointing to his innocence," Benjamin Todd Jealous, president of the NAACP, wrote in an op-ed last week.

The case has received international attention and prominent figures such as Pope Benedict XVI, former President Jimmy Carter, Archbishop Desmond Tutu, and former FBI director William Sessions have made statements on Davis’ behalf, questioning the veracity of the conviction. Even the judge that presided over his 2010 evidentiary hearing stated in his ruling that the state’s case against Davis is not "ironclad." But Georgia seems intent on executing Davis anyways. NAACP, Amnesty International, Color of Change and other organizations are circulating petitions and other action items, urging the Georgia Board of Pardons and Parole to grant Davis clemency and stop the execution.