Obama is also expected to say the U.S. will make a renewed effort to transfer detainees out of the Navy-run detention center for terrorist suspects at Guantanamo Bay, Cuba, to other countries. Obama recently restated his desire to close Guantanamo, a pledge he made shortly after his inauguration in January 2009.
That effort, however, has been stymied because many countries don't want the detainees or are unwilling or unable to guarantee that once transferred detainees who may continue to be a threat will not be released.
There are currently about 166 prisoners at Guantanamo, and 86 have been approved for transfer as long as security restrictions are met.
Obama is also expected to make the case that the U.S.-led war in Afghanistan has decimated al-Qaida's core, even as new threats emerge elsewhere.
In his letter, the attorney general said the decision to target Anwar al-Awlaki was subjected to extensive policy review at the highest levels of the government. Senior U.S. officials briefed the appropriate committees of Congress on the possibility of using lethal force against Anwar al-Awlaki.
The administration informed the relevant congressional oversight committees that it had approved the use of lethal forces against Anwar al-Awlaki in February 2010, well over a year before the operation, Holder said.
A move to gradually shift responsibility for the bulk of U.S. drone strikes from the CIA to the military has already begun. And, according to an administration official speaking on condition of anonymity because he wasn't authorized to speak publicly, the move would largely divide the strikes on a geographical basis, with the CIA continuing to conduct operations in Pakistan, while the military takes on the operations in other parts of the world.
Officials suggest that the CIA strikes into Pakistan have been successful, and point to the agency's ability to gather intelligence there. So, there is less of an inclination to change that now.
In other countries, such as Yemen, Somalia or portions of North Africa, the Defense Department will handle the drone strikes as regular military operations.
In March, the Senate confirmed John Brennan to be CIA director after the Obama administration agreed to demands from Republicans and stated explicitly there are limits on the president's power to use drones against U.S. terror suspects on American soil.
Laura Murphy, director of the American Civil Liberties Union's Washington legislative office, said the administration should "produce the legal rationale that allows him to unilaterally decide when drones can be used .<!p>.<!p>. and we would like him to clarify why he feels he has the authority to use drones outside of the battlefield and how he's going to constrain that authority."
Frank Cilluffo, White House domestic security adviser to President George W. Bush, said Wednesday that the fact that the U.S. targeted al-Awlaki and killed three other U.S. citizens in drone strikes should have been part of the public discourse all along.
He said there had been a lingering narrative that Awlaki was an inspirational leader, while in reality he had a key role in multiple operations targeting Americans. "The fact that they are making this public provides justification for the actions they took," said Cilluffo, now director of a homeland security studies program at George Washington University.