Just think about this for a minute. Barack Obama, like George Bush before him, has claimed the authority to order American citizens murdered based solely on the unverified, uncharged, unchecked claim that they are associated with Terrorism and pose "a continuing and imminent threat to U.S. persons and interests." They're entitled to no charges, no trial, no ability to contest the accusations. Amazingly, the Bush administration's policy of merely imprisoning foreign nationals (along with a couple of American citizens) without charges -- based solely on the President's claim that they were Terrorists -- produced intense controversy for years. That, one will recall, was a grave assault on the Constitution. Shouldn't Obama's policy of ordering American citizens assassinated without any due process or checks of any kind -- not imprisoned, but killed -- produce at least as much controversy?
Obviously, if U.S. forces are fighting on an actual battlefield, then they (like everyone else) have the right to kill combatants actively fighting against them, including American citizens. That's just the essence of war. That's why it's permissible to kill a combatant engaged on a real battlefield in a war zone but not, say, torture them once they're captured and helplessly detained. But combat is not what we're talking about here. The people on this "hit list" are likely to be killed while at home, sleeping in their bed, driving in a car with friends or family, or engaged in a whole array of other activities. More critically still, the Obama administration -- like the Bush administration before it -- defines the "battlefield" as the entire world. So the President claims the power to order U.S. citizens killed anywhere in the world, while engaged even in the most benign activities carried out far away from any actual battlefield, based solely on his say-so and with no judicial oversight or other checks. That's quite a power for an American President to claim for himself.
Presidential assassinations of U.S. citizens - Glenn Greenwald - Salon.com