WASHINGTON (Reuters) - In April 2014, the administration of President Barack Obama announced the most ambitious clemency program in 40 years, inviting thousands of jailed drug offenders and other convicts to seek early release and urging lawyers across the country to take on their cases.

Nearly two years later the program is struggling under a deluge of unprocessed cases, sparking concern within the administration and among justice reform advocates over the fate of what was meant to be legacy-defining achievement for Obama.

More than 8,000 cases out of more than 44,000 federal inmates who applied have yet to make it to the U.S. Department of Justice (DOJ) for review, lawyers involved in the program told Reuters. That is in addition to about 9,000 cases that are still pending at the DOJ, according to the department’s own figures.

Only 187 inmates have had their sentences commuted, far below the thousands expected by justice reform advocates and a tiny fraction of the 2.2 million people behind bars in the United States, which has the world’s highest incarceration rate.

The administration said it wanted to decide on all the applications before Obama’s term ends next January, when the program will automatically expire.

A senior DOJ official told Reuters it is calling on the lawyers’ group -- Clemency Project 2014 -- to simply hand over the outstanding cases without further vetting, saying it is not working fast enough. So far, the group estimates it has handed over around 200 cases.

But criminal justice experts say the administration itself should bear much of the blame. The idea to tap pro-bono attorneys to help vet the cases originated with the DOJ, and critics say it should have prepared its own staff to handle the large volume of applications.

“It’s unfair to criticize the volunteer group that you asked to help,” said Rachel Barkow, a criminal law professor at New York University who has studied clemency in U.S. prisons.

She estimates that about 1,500 prisoners should be eligible for commutation, saying the 187 granted so far does not “fulfill the promise of the program.”

U.S. President Barack Obama speaks to reporters during his visit to the El Reno Federal Correctional Institution outside Oklahoma City in this July 16, 2015 file photo. REUTERS/Kevin Lamarque/Files

The DOJ declined to comment when asked for its response to such criticism.

The delays have left prisoners like Linda Byrnes, 69, in limbo.

“I thought clemency was for people like me,” Byrnes told Reuters through an electronic messaging system from a federal prison in Alderson, West Virginia.

Byrnes, who has spent 20 years in prison for distributing marijuana and has two years left on her sentence, was recently diagnosed with mouth cancer and has yet to hear whether she has been assigned a lawyer after submitting her application to Clemency Project in August 2014.

Obama, who has commuted more sentences than the past five presidents combined, has been a stern critic of harsh U.S. sentencing policies that he says have disproportionately burdened minorities.

Federal life sentences have fallen since Obama took office, from 280 in fiscal year 2009 to 153 in 2013, according to the U.S. Sentencing Commission. About three quarters of the sentences were given to minorities and most were for non-violent offences, the report said.

Clemency Project 2014 said it does not comment publicly on the individuals it represents.

The group vets the applications, writes the petitions and sends them to the Justice Department’s Office of the Pardon Attorney, which oversees all pardons and sentence commutations and makes recommendations for the president’s approval.

So far, 25,000 of 34,000 applications received by Clemency Project have been rejected for failing to meet the basic criteria - no record of violence, no significant ties to a gang or drug cartel, good behavior in prison and completion of at least 10 years of sentence. About 10,000 inmates did not go through the Clemency Project and either applied directly to DOJ or through a paid attorney. “It really would be a sad state of affairs if individuals who had asked for a lawyer weren’t considered in time because their petitions never reached the pardon attorney’s office,” a DOJ official told Reuters on the condition of anonymity.

(Graphic on the clemency bottleneck: tmsnrt.rs/1VThxVT)

“CRITICAL ROLE”

A large number of mostly unqualified applications, a shortage of lawyers and the complexity of the cases have slowed progress, said Cynthia Roseberry, project manager for Clemency Project 2014.

“There are a lot of gray areas,” said Roseberry, who estimates it takes 30 days for one lawyer to review one case on average. “We’ve got to unpack each of these applicants to see specifically what factors affect them... and so that takes a little more time.”

This includes finding pre-sentencing reports for each case, determining if the person would have received a shorter sentence under current law and reviewing prison behavior records.

Roseberry said the group was unaware of any request from the Justice Department to hand over the pending applications. Roseberry said the group’s initially slow pace has picked up in recent months.

The Justice Department declined to elaborate on its private communication with the lawyers.

The Pardon Attorney’s office has brought in personnel from other parts of the department to help to speed up reviews of petitions, the DOJ official said.

Roseberry said about 3,000 applicants still need to be assigned to a lawyer, and that it was not certain whether the group will be able to submit all of the applications it has received before Obama leaves office.

The group has more than 570 law firms and 30 law schools contributing to the effort.

Some rejected prisoners and those who have yet to hear a decision say they believe they would have had a better chance if they had sent their clemency petition directly to the government.

Josie Ledezma was sentenced to life for conspiracy to transport cocaine and applied for clemency through Clemency Project 2014. She said she did not hear from them for six months and later learned that her assigned lawyer had shut down her legal practice. In January, nearly one year after applying, she was told Clemency Project 2014 could not help her and encouraged her to apply directly.

“I wrote back and asked what was it that made me not qualify, but never got a response,” Ledezma told Reuters through an electronic messaging service for federal prisoners.