Spotted this in the WSJ:

Who gets on the drone approved “kill lists” is decided by a complex interagency process involving the CIA, Pentagon and White House. We hear the U.S. could have taken out the radical cleric Anwar al-Awlaki after his contacts with Fort Hood shooter Major Nidal Hassan came to light in November, missing the chance by not authorizing the strike. Perhaps al-Awlaki’s U.S. citizenship gave U.S. officials pause, but after he joined the jihad he became an enemy and his passport irrelevant. (emphasis added)

So the U.S. had a bead on former San Diego imam/grad student/FBI investigative subject? Might this explain the confused initial reports from the Embassy of Yemen that Awlaki had been at the site of a Dec. 24 airstrike?