The U.S. has not declared war since World War II. If the president knows that an attack on our shores is imminent, he'd be hard-pressed to argue convincingly that a guy in a truck in a desert 10,000 miles from here -- no matter his intentions -- poses a threat to the U.S. so imminent and certain that he needs to be killed on the spot in order to save the lives of Americans who would surely die during the time it would take to declare war on the country that harbors him, or during the time it would take to arrest him. Under no circumstances may he use civilian agents for non-judicial killing. Surely, CIA agents can use deadly force to protect themselves, but they may not use it offensively. Federal laws against murder apply to the president and to all federal agents and personnel, wherever they go on the planet.
Since 9/11, the United States government has set up national security systems that function not under the Constitution, not under the Geneva Conventions, not under the rule of law, not under the rules of war, not under federal law, but under a new secret system crafted by the Bush administration and personally directed by Obama, the same Obama who condemned these rules as senator and then extended them as president. In the name of fighting demons in pick-up trucks and wars that Congress has never declared, the government shreds our rights, taps our cellphones, reads our emails, kills innocents abroad, strip searches 87-year-old grandmothers in wheelchairs and 3-year-old babies in their mothers' arms, and offers secrecy when the law requires accountability.
Obama has argued that his careful consideration of each person he orders killed and the narrow use of deadly force are an adequate and constitutional substitute for due process. The Constitution provides for no such thing. He has also argued that the use of drones to do his killing is humane since they are "surgical" and only kill their targets. We know that is incorrect. And he has argued that these killings are consistent with our values. What is he talking about? The essence of our values is the rule of law, not the rule of presidents.