President Barack Obama
President Barack ObamaReuters

President Barack Obama will grant lawmakers access to secret documents outlining the legal justification for drone strikes that kill American citizens abroad who conspire with Al-Qaeda.

An administration official disclosed the reversal of policy Wednesday on the eve of a Senate hearing on Obama's nomination of his top White House anti-terror adviser John Brennan to lead the Central Intelligence Agency in his second term, AFP reported.

A number of senators have warned they would use Brennan's confirmation as leverage to impel the administration to divulge more information on the legal and constitutional grounds for the U.S. government killing American citizens.

The disclosure also comes after NBC News published an unclassified Justice Department white paper covering similar ground, reigniting the debate about the killing of estranged Americans who switched sides in the "War on Terror."

"Today, as part of the president's ongoing commitment to consult with Congress on national security matters, the president directed the Department of Justice to provide the congressional intelligence committees access to classified Office of Legal Counsel advice related to the subject of the Department of Justice white paper," the official said.

Obama aides insist killing Al-Qaeda suspects, including occasionally American citizens, in hotspots like Yemen, complies with United States law and the Constitution, even in cases in which there is no intelligence linking the targets to specific attack plots.

"We conduct those strikes because they are necessary to mitigate ongoing actual threats, to stop plots, to prevent future attacks and, again, save American lives," White House spokesman Jay Carney said Tuesday.

"These strikes are legal, they are ethical and they are wise."

Among the most controversial of the attacks were the September 2011 killings in Yemen of Anwar al-Awlaki and Samir Khan, which fueled a heightened sense of concern because the suspects were U.S. citizens who had never been charged with a crime.

Senator Ron Wyden (D-OR) has been among the most vocal of lawmakers demanding to know details of how the administration interprets its power to take out American citizens who are waging war against the United States.

Wyden asserts that lawmakers need to see the information in order to ensure that such power was subject to the appropriate safeguards and limitations.

"Every American has the right to know when their government believes that it is allowed to kill them," the senator said Tuesday, according to AFP.

"I will continue to press the administration to provide Congress with any and all legal opinions that outline the president's authority to use lethal force against Americans.

I will not be satisfied until I have received them," he said.

The white paper published by NBC News offers a more expansive definition of when a drone strike against a U.S. citizen can be justified than has been available in the past.

Extracted from the secret documents that will now be made available to congressional committees with jurisdiction over the war on terror, the memo expands on the concept of self-defense used to justify an attack.

It also states that an attack against the United States or its interests by a targeted person does not need to be deemed as "imminent" for a strike to take place.

"The condition that an operational leader present an 'imminent' threat of violent attack against the United States does not require the United States to have clear evidence that a specific attack on US persons and interests will take place in the immediate future," the memo says.

Instead, an "informed, high-level" official could decide that the target posed "an imminent threat of violent attack against the United States" if he had "recently" engaged in such activities, and there was no evidence he had renounced or abandoned the acts.

The 16-page memo also says the individual's capture must be unfeasible, which includes situations where capture would pose an "undue risk" to American personnel.

Civil liberties groups were dismayed by the memo, arguing that the president was assuming powers to kill U.S. citizens without presenting evidence to a judge or even informing the courts about an attack after the fact.

"While we commend the administration for providing documents requested by Congress, secret disclosure of the administration's justification to the Senate intelligence committee is insufficient," said director of Human Rights First's Law and Security Program, Dixon Osburn.

"Only complete public disclosure of the legal justifications behind the US targeted killing program can assure Americans that the United States is complying with the law and established rule. The United States targeted killing program is setting a precedent for the rest of the world,” he said. “We have to get this right."