Updated

A contentious federal appeals court nominee narrowly cleared a key Senate hurdle on Wednesday, as the administration tried to ease concerns about the candidate's role in crafting the legal rationale for using drones to kill American terrorist suspects abroad.

The Senate voted 52-43 to advance the nomination of David Barron for a seat on the 1st U.S. Circuit Court of Appeals, based in Boston. The move sets up a final vote for Thursday.

The vote comes after the Obama administration, under pressure from members of both parties, agreed to release a censored version of one of Barron's drone memos. At the Justice Department in 2009 and 2010, Barron wrote memos that asserted the government's right to kill Americans overseas who are believed to be terrorists. Barron, now a Harvard Law School professor, also worked at the department in the Clinton administration.

It was not immediately clear when that document will be disclosed. But the decision to not fight a federal appeals court order to release it won over at least two Democrats who had demanded that it be made public.

Sen. Ron Wyden, D-Ore., said it will be "a very constructive step" for the administration to release the document.

"I believe that every American has a right to know when their government believes it has a right to kill them," Wyden said.

Sen. Rand Paul, R-Ky., though, was not convinced and continued to fight the nomination. "I cannot and will not support a lifetime appointment of anyone who believes it's OK to kill an American citizen not involved in combat without a trial," Paul said Wednesday.

Paul, a possible 2016 presidential candidate, said this week he would oppose Barron under any conditions because killing Americans without a trial is unconstitutional.

Democratic Sens. Mary Landrieu of Louisiana, who is in a tight re-election race, and Joe Manchin of West Virginia were the only lawmakers to cross party lines.

A U.S. drone strike in Yemen in 2011 killed Anwar al-Awlaki, an American who administration officials say became an Al Qaeda leader.

The department has acknowledged that three other Americans also were killed by drones in overseas counterterrorism operations, but that those deaths were inadvertent.

The Associated Press contributed to this report.