(Jim Watson/AFP/Getty Images)

Cliff Sloan, a top Washington lawyer, has been chosen as the State Department's special envoy to close Guantanamo Bay, marking a step forward in what has been an arduous effort to fulfill President Obama's campaign promise to close the prison.

"This announcement reflects the administration's commitment to closing the detention facility at Guantanamo Bay," said State Department spokesman Jen Psaki today.

"Special Envoy Sloan brings a wealth of experience as an accomplished litigator and pragmatic problem-solver, a skill set that will prove valuable as he serves as the lead negotiator for the transfer of Guantanamo detainees abroad and manages the multitude of diplomatic issues related to the president's directives to close the Guantanamo Bay detention facility, implement transfer determination and conduct a periodic review of those detainees who are not approved for transfer."

Sloan, a partner at Skadden, Arps, Slate, Meagher & Flom LLP & Affiliates, has served in both President George H.W. Bush and President Bill Clinton's administrations in the Justice Department and as associate White House counsel.

The news of Sloan's appointment was first reported by The Associated Press on Sunday.

Secretary of State John Kerry praised Sloan in a statement Sunday as the type of "bridge-builder" needed for the role.

"It will not be easy, but if anyone can effectively navigate the space between agencies and branches of government, it's Cliff," Kerry said, according to the Associated Press. "I appreciate his willingness to take on this challenge. Cliff and I share the president's conviction that Guantanamo's continued operation isn't in our security interests."

The effort to close Guantanamo has been stymied by Washington politics and legislation preventing detainees from being transferred from the Cuba facility to the United States. According to the State Department, 166 detainees remain in the facility.

Obama renewed a promise to close the base in a foreign policy speech at the National Defense University in March.

"Given my administration's relentless pursuit of al Qaeda's leadership, there is no justification beyond politics for Congress to prevent us from closing a facility that should never have been opened," Obama said.

He called on Congress to lift restrictions on detainee transfers from Guantanamo Bay to other countries, including the United States.

But the politics remain difficult.

Sloan's predecessor in the role, Daniel Fried, left the post and was reassigned within the State Department in January after making little progress in closing Guantanamo.

"I think the real issues is: Can Mr. Sloan, if he comes up with a similar plan, be able to sell that to the Congress," said Larry Korb, a former assistant secretary of defense and a senior fellow at the Center for American Progress. "I think the answer is there. We all know what to do. The only question is: Is Congress going to put up a roadblock?"

If anything, the job requires a shrewd legal mind to work out the constitutional and legal difficulties inherent in transferring or trying detainees accused of terrorism.

And it also requires a master negotiator with bipartisan credibility.

In a nod to Sloan's appeal across the ideological aisle, the State Department offered up testimonials from several prominent figures, including former solicitor general Ken Starr, who served as independent counsel during Bill Clinton's impeachment proceedings.

Sloan was also the editor-in-chief of Slate magazine, and he was part of the legal team defending former senator and Democratic presidential contender John Edwards against allegations that he violated campaign finance law.

"He worked for Clinton and for Bush, so he's got that. If you look at people who vouch for him they include Ken Starr and [Former Supreme Court Justice] John Paul Stevens," Korb said. "It's not like you can say this is some liberal Democrat who wants to let everyone go free."