President Obama pauses as he speaks at the El Reno Federal Correctional Institution in Oklahoma in July 2015. (Evan Vucci/AP)

A longtime federal prosecutor became the acting U.S. pardon attorney this week, taking over a critical Obama administration position in the president’s high-profile effort to grant clemency to more federal drug offenders during his last year in office.

Bob Zauzmer, 55, an assistant U.S. attorney for 26 years in Philadelphia, will head a Justice Department office with 12 lawyers that is struggling to process a backlog of more than 9,000 clemency petitions. His predecessor, Deborah Leff, left last week, after saying she could not get the resources­ she needed to do her job.

Under an initiative started in 2014 to give relief to nonviolent drug offenders who received harsh mandatory sentences, then-Attorney General Eric H. Holder Jr. said prisoners could be considered for clemency if they have served at least 10 years; have no significant criminal history and no connection to gangs, cartels or organized crime; and probably would have received a substantially lower sentence if convicted of the same offense today.

“This is something I really passionately believe in,” Zauzmer said in an interview. “I am delighted that we have a president who is willing to examine and address sentences that were imposed many years ago that were troubling at the time, and to take a fresh look and decide whether based on current law and current understanding we can give lower sentences.”

About 33,000 federal inmates initially applied for the early release. Hundreds of lawyers working pro bono for the group Clemency Project 2014 have been sifting through those applications to find prisoners who meet the criteria. They then write the petitions and send them to the Office of the Pardon Attorney, which oversees all pardons and sentence commutations and makes recommendations for the president’s approval.

Bob Zauzmer, a longtime federal prosecutor, has been named the acting U.S. pardon attorney. (Department of Justice/Department of Justice)

Zauzmer’s recommendations will first go to Deputy Attorney General Sally Quillian Yates, who then decides which petitions to recommend to White House Counsel W. Neil Eg­gleston.

Obama has commuted the sentences of 184 federal inmates, more than the past five presidents combined. But advocates of sentencing reform are disappointed that the process hasn’t moved more quickly and that more of the thousands who have submitted clemency petitions have not had their sentences commuted. A Justice Department official said this week that the petitions have been prioritized in terms of which ones most clearly meet the department’s criteria.

Zauzmer said he hopes to get more resources­ soon. The Justice Department is awaiting congressional approval to double the pardon attorney’s staff from 22 to 46.

“We’re all well aware of the calendar, so we know that if we’re going to get help, it has to come soon,” Zauzmer said. But he added that whether he gets more resources­ or not, he is determined to “work with the resources­ we have” this year.

“I have one goal and that is to look at every single petition that comes in and make sure an appropriate recommendation is made to the president,” he said.

Zauzmer, the father of three (one is a Washington Post reporter), is a graduate of UCLA and Stanford Law School. After a clerkship with Judge Arlin M. Adams of the U.S. Court of Appeals for the 3rd Circuit, he worked in private practice for three years before joining the U.S. attorney’s office in Philadelphia in 1990. As a trial prosecutor he focused on corruption and fraud cases, and since 1998, he has supervised criminal appeals. He also is an adjunct faculty member at the University of Pennsylvania Law School, where he teaches a seminar on appellate advocacy.

From 2012 to 2014, Zauzmer served on a committee advising Holder and testified on behalf of the department before the U.S. Sentencing Commission about changes­ in sentencing guidelines — an effort separate from Obama’s clemency initiative.

“When it comes to criminal justice reform, Bob Zauzmer has both his head and his heart in the game,” Holder said.

Heather Childs, chief of staff to Yates, said that when the Sentencing Commission lowered the drug guidelines two years ago, making potentially 46,000 of the nation’s approximately 100,000 federal drug offenders eligible for early release, Zauzmer was “the go-to guy in getting that implemented.” For each inmate, a federal judge had to approve the early release, which allowed for the first group of 6,000 inmates to be released last fall.

“When we had to deal with tens of thousands of motions across the country, he’s the guy who figured out how we do that efficiently and to the maximum extent possible,” Childs said. “With that experience, which mirrors what we’re dealing with in the Pardon Attorney’s Office . . . he’s really perfect. He understands the urgency and importance.”

Zauzmer said he is not discouraged by the huge backlog of clemency petitions and the fact that his predecessor left, frustrated by a lack of resources.

“To me, daunting is not the first word that jumps in my mind,” he said. “The first word is excited and privileged to have the opportunity. There’s a tremendous amount of work. We will figure this out and get it done.”