WASHINGTON // The US president Barack Obama's nominee for CIA director is expected to face an unprecedented public grilling at his Senate confirmation hearing today over the legal justifications of the administration's covert drone programme that it has fought to keep secret even from Congress.
The confirmation process of John Brennan, who oversaw the vast expansion of the targeted killing programme, could be complicated by legislators who have grown increasingly frustrated at the administration's refusal to reveal its legal reasoning for killing Americans abroad.
The clearest picture yet of this reasoning was revealed in a leaked Justice Department "white paper", first reported on Monday by NBC News, that outlines the administration's decision to kill suspected Al Qaeda members without any evidence of their involvement in an imminent plot.
In the week leading up to Mr Brennan's hearing a report also revealed startling facts about the scale of the CIA's extraordinary rendition programme and interrogation techniques while he was a senior official at Langley under former president George W Bush.
Mr Brennan's role as a senior CIA official under Mr Bush forced him to withdraw his nomination to head the CIA during Mr Obama's first term, though it is considered unlikely that he will not be confirmed this time.
"The parallels to the Bush administration torture memos are chilling," said Vincent Warren, the executive director of the Centre for Constitutional Rights in New York. "Those were unchecked legal justifications drawn up to justify torture; these are unchecked justifications drawn up to justify extrajudicial killing."
The leaked "white paper" on drone strikes appears to have come from a member of Congress to increase pressure on the administration to release the legally binding memos, details of which the paper only hints at, which it has so far fought in court to keep secret.
The administration argues that even if such memos did exist, they should be considered classified legal advice not meant for congressional oversight.
At a White House press conference on Tuesday, spokesman Jay Carney said the administration had no intention of releasing the "alleged memos".
The leaked paper will also drive the discussion at today's confirmation hearing and put Mr Brennan on the defensive.
Democratic senator Ron Wyden said on Tuesday he was unsatisfied with the leaked memo, which had been given in confidence to members of Congress last year in an attempt to add transparency, and said he would push Mr Brennan to clarify during the hearing.
"[He] is the architect of the administration's counterterrorism policy," Mr Wyden told The Washington Post. "If the Congress doesn't get answers to these questions now, it's going to be extremely difficult, if not impossible, to get them in the future."
Mr Wyden, who sits on the Senate Select Intelligence Committee that will conduct the hearing, has led the charge for more transparency on drone strikes and on Monday sent a letter signed by 11 Democratic and Republican senators to Mr Obama urging him to release the legal opinions.
Without those documents, it is impossible for Congress and the public to decide "whether this authority has been properly defined, and whether the president's power to deliberately kill Americans is subject to appropriate limitations and safeguards", the senators wrote.
The "white paper" lacks, for example, the threshold of evidence that was passed to justify the drone strike on Anwar Al Awlaki, the American preacher killed in Yemen in 2011.
It does show, however, for the first time that the administration stretches the definition of "imminence" to its limit, saying it can kill alleged Al Qaeda members without any evidence they are plotting against the US and if capture is not feasible.
It also states that the decision to kill would not be subject to judicial review.
The hearing will also delve into Mr Brennan's 25-year career with the CIA, especially under the the Bush administration, when he served as deputy executive director from 2001-2003. He then served in other senior counterrorism roles, thought not specifically with the agency .
A classified 6,000-page Senate report on the CIA's interrogation programme during the Bush years is reported to have found that the interrogations were often mismanaged and that officers did not always tell the truth about torture and other techniques to senior officials or even the White House.
Mr Brennan has said he opposed torture techniques such as waterboarding, but other former CIA officials reportedly dispute this.
A report released on Monday by the Open Society Foundation gives the most detailed public disclosure so far of the CIA's extraordinary rendition programme, in which suspected terrorists were captured and taken to secret prisons abroad and often tortured, or given to foreign intelligence services to torture.
Mr Brennan's role in this programme is also expected to be questioned in today's hearing.
The report revealed that "fifty-four countries were complicit in the programme, or more than a quarter of all governments on the planet", said Joshua Foust, a counterterrorism expert at the American Security Project think tank in Washington.
"What the report says is that the scale at which the US was engaged in capturing, transferring and ultimately interrogating people to various levels of legality was absolutely astonishing," he said. "And John Brennan was in the middle of all that."
*With additional reporting from Associated Press