Two days before President Obama left office in January, he denied Native American activist Leonard Peltier's application for clemency that would have meant an early release from prison. The International Leonard Peltier Defense Committee has since hired David Frankel, a civil rights attorney and former prosecutor, to revive Peltier’s fight for freedom. And to help cover legal expenses, Kris Kristofferson will headline a benefit concert Nov. 6, at the Bank of Oklahoma Center in Tulsa, Oklahoma.

Joining him are the folk and country artists Jamey Johnson, Arlo Guthrie, Jessi Colter, Shooter Jennings, Rita Coolidge, Joe Ely, Doors drummer John Densmore and Folk Uke. Video messages from Peter Gabriel, Tom Morello and Steven Van Zandt will also be played.

During a shootout on an Indian reservation in 1975, two F.B.I. special agents were murdered execution-style. Nobody knows who fired first. Nobody saw Peltier kill the detectives. Yet he was sentenced to back-to-back life terms and has served 40 years.

Last month, days before Peltier turned 73, he underwent sudden heart surgery at a high-security prison in Florida. Peltier’s poor health could help his chances for parole, Frankel told Billboard. He’ll be eligible in 2024.

“At this point, this is a matter of simple mercy,” Guthrie told Billboard. “There’s no direct proof that this guy committed a crime. In cases like this, we should err on the side of compassion.”

Peltier “represented the F.B.I.’s last chance to obtain a conviction” in the reservation murders after two Native Americans were acquitted, Peter Matthiessen argued in his 1983 book, In the Spirit of Crazy Horse.

“They needed somebody to take the fall,” said Connie Nelson, who organized the benefit concert. Many of Peltier’s supporters claim racism drove much of his prosecution. “We kind of wiped out the Native Americans when we came over here,” Densmore told Billboard. “You gotta admit that, or you can’t move on and clean up the other stuff.”

Peltier is among only two percent of federal inmates who are Native American.

Resistance to Peltier’s freedom is “rooted in race,” the civil-rights activist Harry Belafonte told Billboard. Reached by phone on Peltier’s birthday, Belafonte added, “There’s been no specific story coming from the opposition that tells you why they feel Peltier must be held in bondage in the face of this overwhelming proof that he is not the guilty person.”

Peltier’s opponents insist his conviction was justified.

“Whether planning to or not, Peltier was there and participated in the murder of two federal agents,” Ed Woods, a former F.B.I. agent and the founder of the No Parole Peltier Association, wrote in an email. He added that Peltier’s version of the shootings has changed over the years.

“I did exchange fire with the authorities who were shooting at us,” Peltier told The Daily News in 2016, “but I didn't kill those agents.”

Following Peltier's trial, documents revealed that prosecutors had misrepresented certain evidence. They later admitted that a shell casing could not be linked to Peltier's rifle. Those findings, as well as a Robert Redford documentary on the case, failed to convince the government to grant a new trial.

Three presidents have refused to free Peltier early. Today, the former U.S. attorney whose office prosecuted Peltier wants him released.

“The most proof we had was the fact that he was there,” said James Reynolds, who appealed for clemency in a letter to Obama. Though he’s not convinced of Peltier’s innocence, Reynolds added that jailing him is no longer beneficial to society. “I thought that enough time had passed. And in the interest of justice, it was time to move onto something else.”

“To think that Trump would grant a pardon, after Obama was a big disappointment in rejecting it, is hard to fathom,” said Terry Gilbert, Peltier’s former attorney.

“For me, that was the worst thing that Obama did,” said the Native American musician Rita Coolidge, who will play the benefit. “Hopefully this will be the step that gets that door open for Leonard to walk through.”

Peltier’s lawyer said a renewed petition for parole will highlight the racial discrimination and the F.B.I.’s “underhanded tactics” during the 1977 trial. Frankel will also pursue a compassionate release for Peltier, a reprieve generally reserved for inmates with terminal illnesses. In August, senators called on the Federal Bureau of Prisons to expand the program.

“I once asked him about his frustration and why does he linger on,” Belafonte recalled. “He said, ‘What else do I have to do but rely on hope?’”