The US Senate Intelligence Committee on Tuesday endorsed John Brennan to be the next CIA director, after the White House turned over secret memos on the targeted killing of Americans.
Senators voted by 12 votes to three to approve Brennan, putting him on track to be President Barack Obama's third confirmed national security nominee, after Secretary of State John Kerry and Pentagon chief Chuck Hagel.
A full Senate vote on Brennan's confirmation is expected this week.
"No one is better prepared to be CIA director than Mr. Brennan," committee chair Senator Dianne Feinstein said in a statement announcing the vote.
Brennan has been subjected to a two-month confirmation process, with some US lawmakers insisting that questions remain about his nomination or using it as leverage to force the White House to release it more classified information.
Republicans notably wanted answers about the secret US drone program and a deadly attack on US diplomats on September 11, 2012 in Benghazi, Libya.
They got much of it on Tuesday, when the White House agreed to release more material, including secret Justice Department memos on the president's powers to authorize the killing of Americans in counter-terror operations.
"Just last night I reached agreement with the White House to review all OLC (Office of Legal Counsel) opinions on targeted killings of Americans," Feinstein said.
"It was unfortunate these issues delayed the process, but I am confident that they have been resolved."
The committee's top Republican, Senator Saxby Chambliss, said he voted against Brennan due to "inconsistencies" in his testimony last month.
"I think we've got to have a stronger trust relationship with the CIA than what I felt like Mr. Brennan could bring," he told reporters.
But he said he would not encourage his colleagues to try to hold up the nomination, adding he expected "he'll probably be confirmed."
The White House acknowledged that it was turning over the memos to lawmakers in part to "help expedite confirmation" of Brennan.
"On the merits, John Brennan is a uniquely and highly qualified nominee to be the next director of the CIA," White House spokesman Jay Carney told reporters.
The White House material included a letter from Attorney General Eric Holder in which he said US forces could launch a drone strike against a target on US soil if there was an "extraordinary circumstance."
In a letter to Republican Senator Rand Paul, the nation's top Justice Department official insisted that US military and intelligence agencies had "no intention" of carrying out such an attack, but he did not rule it out.
"It is possible, I suppose, to imagine an extraordinary circumstance in which it would be necessary and appropriate under the Constitution and applicable laws of the United States for the president to authorize the military to use lethal force within the territory of the United States," Holder wrote.
Paul branded Holder's written comments "more than frightening."
Three Americans are known to have been killed in US drone strikes, including Al-Qaeda propagandist Anwar al-Awlaki. They were targeted in Yemen, not on US soil, but questions have been raised about the legitimacy of the tactic.
Brennan, 57, is a 25-year veteran of the Central Intelligence Agency.
For the past four years he has worked as the top White House counter-terror expert, but he is most contentiously known as the architect of the US drone war in countries like Pakistan and Yemen.
A bipartisan group of senators including Democrat Ron Wyden and Republican Susan Collins meanwhile claimed victory, in their push for greater access to the documents outlining Obama's authority.
They also called for Congress "to consider ways to ensure that the president's sweeping authorities are subject to appropriate limitations, oversight, and safeguards."