The U.S. Senate on May 16 confirmed Jeffrey Rosen to be the next deputy attorney general. Rosen was confirmed along party lines by a vote of 52 to 45.

He replaces former Deputy Attorney General Rod Rosenstein, whose last day at the Department of Justice was May 11. Rosenstein oversaw special counsel Robert Mueller’s investigation into Russian interference in the 2016 election before the investigation was handed to Attorney General William Barr.

Rosen most recently was deputy secretary of the U.S. Department of Transportation. Before assuming that role, Rosen was a senior partner at Kirkland & Ellis, where he had worked for nearly 30 years before and after two public-service appointments. He was previously appointed as general counsel and senior policy advisor for the White House Office of Management and Budget from 2006 to 2009, and as general counsel at the U.S. Department of Transportation from 2003 to 2006.

Appointed by the President with the consent of the Senate, the deputy attorney general is the Justice Department’s second highest ranking official. The mission of the Office of the Deputy Attorney General is “to advise and assist the Attorney General in formulating and implementing Department policies and programs and in providing overall supervision and direction to all organizational units of the Department,” according to the agency.

Some Democrats have argued Rosen is not qualified to serve in this position. “At this critical moment, we need a deputy attorney general who knows the Justice Department, who has experience in criminal investigations and prosecutions, and who is committed to the Department’s role of enforcing the law independently,” U.S. Senator Dick Durbin (D-IL) said in a statement in response to the vote.

“Mr. Rosen has no experience working in the Justice Department or handling criminal cases,” added Durbin, who also serves as the Democratic Whip, the second highest ranking position among the Senate Democrats. “Mr. Rosen simply does not have the qualifications for this critical assignment.”

In his testimony, Rosen noted that he is not the only deputy attorney general who is joining the agency with no experience as a federal prosecutor. “There have been 37 Deputy Attorneys General, thus far, some who had served as federal prosecutors at the Department, some who had served in legal roles at other departments, and some who had worked primarily in private law firms,” he said. “I fall in the latter two categories, so if confirmed would expect to draw fully on the extraordinary lawyers with prosecutorial experience at the Department, including some in what would be my immediate office, as well as throughout the Department of Justice.”