President Obama has ordered an early release from prison for Clarence Aaron, who has spent twenty years there, hoping for mercy.

Aaron’s commutation is one of eight crack cocaine-related sentences commuted today. Obama said the sentences were meted out under an “unfair system” that among other things featured a vast disparity between crack and powder cocaine cases.

The White House ordered a new review of Aaron’s petition last year after ProPublica and the Washington Post reported that the government’s pardon attorney, Ronald Rodgers, had misrepresented Aaron’s case to President George W. Bush. An Inspector General’s report released last December supported ProPublica’s findings, and referred the incident to the Deputy Attorney General to determine if “administrative action is appropriate.”

The Justice Department did not immediately respond to our questions about the status of the Deputy Attorney General’s review.

As a first-time, non-violent drug offender sentenced to three life terms in 1993, Aaron had seemed a model candidate for presidential mercy. He first applied for a commutation – meaning early release – in 2001.

“He was just overcome,” said his attorney, Margaret Love, who spoke with Aaron this morning shortly after he received the news. “We’re very grateful to the president.”

Aaron’s release is effective April 17, though Love said he may go home sooner.

The president also announced thirteen pardons today. Before that, Obama had issued 39 pardons and commuted one sentence, granting clemency at a lower rate than any other president in recent history. (While a commutation grants early release, pardons are given to people who have already served their sentences or have never been jailed, restoring for instance their right to vote.)

When asked about Obama’s low clemency rate at a recent press conference, Attorney General Holder said “We are at year five I guess of eight, so I would say hold on.”

Prominent lawyers have called for an overhaul of the pardons system and the way in which recommendations are made to the president. ProPublica found major racial disparity among successful pardon applicants. The Justice Department has commissioned its own study of race and clemency, which as of August, it said was “ongoing.”

Holder made no mention of pardons in a major speech on criminal justice reform this summer, but spoke against “draconian mandatory minimum sentences,” and a system in which “too many Americans go to too many prisons for far too long.”

The fact that the commutations all involved crack cocaine, Love said, “says something very important about the long federal sentences for drug crimes. There are a lot of people in prison whose cases are similar to the ones being commuted.”

“Now that the president has opened the door to doing commutations, he might make it a more regular activity, and not just save it for the holidays or the end of his term,” said Julie Stewart, president of the group Families Against Mandatory Minimums. “He certainly has plenty of cases that he could choose from. I guess that time will tell.”