Leaked terror memo could complicate Brennan hearing

(CBS News) John Brennan, President Barack Obama's former counter-terrorism adviser, is set to make his case on Capitol Hill to become CIA director. But a leaked memo that spells out the case for killing Americans linked to terrorism will likely complicate Thursday's hearing.

The unclassified memo written by the Justice Department was sent to some members of Congress last summer, but was never intended to be public. It was leaked this week, most likely because the Senate is holding hearings Thursday on the nomination of Brennan to head the CIA. Brennan is the architect of the drone program. But now, the leak has the White House on the defensive.

Administration officials argued forcefully Tuesday that the targeted killing of terrorists who are American citizens -- often by drone strikes -- is acceptable policy in the battle to keep America safe. White House Press Secretary Jay Carney has said, "These strikes are legal, they are ethical, and they are wise."

Attorney General Eric Holder has said these types of actions are taken only when there is an "imminent threat, when capture is not feasible and when we are confident that we are doing so in a way that is consistent with federal and international law."

But the administration gives itself wide latitude on what constitutes an "imminent threat."

The memo reads that the administration "does not require ... clear evidence that a specific attack ... will take place in the immediate future." And a U.S. citizen can be targeted "if they're believed to be a senior operational leader of al-Qaeda ... engaged in planning operations to kill Americans."

Anwar al-Awlaki was the highest profile American-born jihadi killed by a targeted drone strike. Another American, Samir Khan, was killed in the same attack in 2011.

CBS News' Bill Plante asked Carney, "What about some kind of review? I mean, you're taking away a U.S. citizen's due process -- doesn't it deserve a broader debate?"

Carney replied, "We understand that these are weighty matters, that these are serious issues, and they deserve the kind of considered approach that this president has taken to them."

White House officials, including Brennan, when he was the president's counter-terrorism adviser, have, in the past, made the case that strikes are in the U.S. national security interest.

Brennan said on April 30, 2012, "The purpose of a strike against a particular individual is to stop him before he can carry out his attack and kill innocents."

Civil liberties groups have been upset with the targeted strike policy since it became public. The American Civil Liberties Union called the leaked memo, which lays out the legal justification for the policy, irresponsible and chilling. You can expect to hear more about it when Brennan goes before the Senate Thursday for his confirmation hearing.

For Bill Plante's full report, watch the video in the player above.