I don't have very much to add to this:
But I would hope that nobody needs me or anyone else to explain why this assertion of power is so pernicious -- at least as pernicious as any power asserted during the Bush/Cheney years. If the President has the power to order American citizens killed with no due process, and to do so in such complete secrecy that no courts can even review his decisions, then what doesn't he have the power to do? Just for the moment, I'll note that The New York Times' Charlie Savage, two weeks ago, wrote about the possibility that Obama might raise this argument, and quoted the far-right, Bush-supporting, executive-power-revering lawyer David Rivkin as follows:
The government's increasing use of the state secrets doctrine to shield its actions from judicial review has been contentious. Some officials have argued that invoking it in the Awlaki matter, about which so much is already public, would risk a backlash. David Rivkin, a lawyer in the White House of President George H. W. Bush, echoed that concern.
"I'm a huge fan of executive power, but if someone came up to you and said the government wants to target you and you can't even talk about it in court to try to stop it, that’s too harsh even for me," he said.
Having debated him before, I genuinely didn't think it was possible for any President to concoct an assertion of executive power and secrecy that would be excessive and alarming to David Rivkin, but Barack Obama managed to do that, too. Obama's now asserting a power so radical -- the right to kill American citizens and do so in total secrecy, beyond even the reach of the courts -- that it's "too harsh even for" one of the most far-right War on Terror cheerleading-lawyers in the nation. But that power is certainly not "too harsh" for the kind-hearted Constitutional Scholar we elected as President, nor for his hordes of all-justifying supporters soon to place themselves to the right of David Rivkin as they explain why this is all perfectly justified. One other thing, as always: vote Democrat, because the Republicans are scary!
This is important in four ways. First, it is a large step beyond even what Bush II did in the war on terror. Asserting the power and authority to kill an American citizen without due process of law is something even Cheney didn't try.
Second, as we know from the torture policies [not to mention simple familiarity with the limits of human knowledge] we can't trust the government to always identify the right person.
Third, by asserting the state secrets doctrine to cover the assassination policy, President Obama and his administration are attempting to remove any check on the power he is asserting. This is especially troubling, because it means that all of the regular checks to keep the misidentification problem under control end up being avoidable. And after-the-fact checks end up being avoidable.
Fourth, even granting the good faith of the current Administration in making sure they have the right guy, and in never using it for improper purposes, how can we trust every future administration with this power?