Mark Hosenball of Reuters wrote a story which sheds slightly more light on the process by which recently deceased Anwar al-Awlaki and others are marked for assassination by the U.S. Government:

American militants like Anwar al-Awlaki are placed on a kill or capture list by a secretive panel of senior government officials, which then informs the president of its decisions, according to officials.

There is no public record of the operations or decisions of the panel, which is a subset of the White House's National Security Council, several current and former officials said. Neither is there any law establishing its existence or setting out the rules by which it is supposed to operate.

Sources again said as far as they knew, al-Awlaki was the only American put on the kill list. The other American killed in the drone strike which took out al-Awlaki was confirmed to have been "collateral" and not an intended target. 

But there is a panel of sorts (described so wittily as a REAL death panel by Adam Serwer of Mother Jones) which decides who will be on the list, but there are some differing accounts of the exact involvement of Obama:

The top Democrat on the House Intelligence Committee, Representative Dutch Ruppersberger, was asked by reporters about the killing.

The process involves "going through the National Security Council, then it eventually goes to the president, but the National Security Council does the investigation, they have lawyers, they review, they look at the situation, you have input from the military, and also, we make sure that we follow international law," Ruppersberger said....

Other officials said the role of the president in the process was murkier than what Ruppersberger described.

They said targeting recommendations are drawn up by a committee of mid-level National Security Council and agency officials. Their recommendations are then sent to the panel of NSC "principals," meaning Cabinet secretaries and intelligence unit chiefs, for approval. The panel of principals could have different memberships when considering different operational issues, they said.... They confirmed that lawyers, including those in the Justice Department, were consulted before Awlaki's name was added to the target list.

The whole thing is well worth reading. As is this Glenn Greewald rant which again highlights how unproven the case against al-Awlaki remains. And he points to a Washington Post article from last year which suggested that al-Awaki was not the only American on the kill list. 

I wrote up some of the less-than-ethusiastic responses to the assassination the day it happened. Jacob Sullum of course recently summed up the potental uses of this power:

While Awlaki may have been guilty of everything the administration claims, it is not hard to imagine how a program of classified, unreviewable death decrees might go awry, especially in the service of a perpetual, geographically undefined war against an amorphous enemy.