Slippery slope

I am quite disturbed by the story of an American citizen Anwar al-Awlaki getting killed by a drone attack by C.I.A. Americans are proud to quote from their constitution their rights as a citizen(first amendment, fourth amendment, so on). I wonder where in the constitution it gives the government the right to kill her citizens without a trial. I hear that it was authorized based on a memo the Obama administration wrote which has the most convoluted and illogical justification for killing a U.S. citizen. Another thing which bothers me is the use if drones to kill suspected enemies (terrorists) of United States. I think hundreds of innocent peoples are killed in the process, which is waved off as ‘collateral damage’. Do people really believe that the drone attack in Yemen surgically killed just two enemies of United States? How many others got killed, I wonder. I notice that the U.S. news media does not mention anything about it. Nobody cares, I guess. I am amazed that this has happened under President Obama who was a teacher of U.S. Constitution! Wonder what will happen if we have another President ignorant and arrogant as George Bush.