Kevin, respectfully I’d suggest that your “assassination” rhetoric is without foundation in the laws of war and our own domestic law. Any individual — American citizen or not — who joins a declared hostile military force in hostilities against the United States becomes a member of that force and a legitimate target. The only distinction between al-Awlaki and, say, someone who decided to join the SS in World War II is that the SS at least complied with the laws of war enough to wear uniforms while committing their unspeakable atrocities.
Those who call this action an assassination are buying the radical Left’s foundational premise about our war: that it is not a war at all but instead a global police action against a particularly dangerous version of the mafia. Under such a formulation, even the bin Laden strike is unlawful (as indeed are all of our kill/capture raids). Yet this law-enforcement model is directly contradicted by the congressional authorization for the use of military force to respond to the 9/11 attacks. Al-Qaeda and all its members are military targets, al-Awlaki was a member of al-Qaeda, and the strike that killed him was entirely justified and appropriate.