This does a fair job of capturing most of what I was stammering about trying to say. The author goes farther than I would on some aspects.

Bot

President Obama authorized the killing of an American citizen because he had declared war on the United States and encouraged others to bring harm to America. Whatever Anwar al-Awlaki's wrongs -- and there were many -- when America kills its own without a trial, it not only demeans itself but it hands over a propaganda victory to its enemies.
Ayman al-Zawahiri, al Qaeda's leader since the death of Osama bin Laden, will chide this great country again for abandoning its values and principles. The White House's authorization of this killing also tells American Muslims that a precedent has been set by their government to kill American citizens abroad without trial if they oppose their country.
This cannot be right -- and is counterproductive to defeating terrorism in the long term because it demolishes the very values that America stands for: the rule of law and trial by jury.

more: U.S. shouldn't have killed al-Awlaki - CNN.com