Traditionally, wars are conflicts between either two or more states or two or more groups within a state. And a state is basically a geographic location that has widely recognized borders that encompasses a group of people who share a common identity as a nation. On top of that, those people within the borders generally have some level of autonomy, meaning they make their own decisions on how their gov't or society should be run. This is kind of a point for another post, but I question the merits of full autonomy of a state in regard to human rights. But at a fundamental level I'm ok with it.
In a traditional sense, I'll grant the Obama administration that we are at war with Afghanistan and Iraq. Part of the problem with Afghanistan was/is that they were shaky with regard to the common identity and autonomy aspects of a state. The Taliban was causing it to be a very unstable state. But for sake of argument, I'll grant that Afghanistan fits the statehood model and we were thus able to go to war with them. Iraq was run by a sociopath. But it was a fairly stable state, at least compared to Afghanistan. So I think also fits the bill.
Defining what constitutes a war is important because under those circumstances, the president has more power to do things it normally wouldn't for the sake of national security. That's why in speeches such as Holder's the point is always made that we are at war. And it's also used to ratchet up fear and invoke loyalty to the administration. But this thing about killing terrorists wherever they are in the world is beyond the scope of the Afghan and Iraq wars. As long as we are legally at war with those states the administration has stronger claims to not use due process when in Afghanistan in Iraq. But they are going beyond those states and into states we aren't at war with in order to find and kill their citizens.
When arguing that they can kill someone they deem a terrorist, even an American citizen (though I don't think that matters), they are claiming that as a country, we are at war with every terrorist or terrorist group in the world. Thus they have the same powers they enjoy in a traditional war. Right away you can see the differences between this new type of war and traditional wars. Terrorists aren't state actors. A terrorist living in France who tries to attack the US is no more a state actor than if I tried to attack France. Thus under those attacks, neither country would declare war on each other. But if the French or US military attacked on another, war would be declared.
When dealing with terrorism, we are dealing with individuals and fairly small groups of individuals. And we are dealing with people who attack civilians as part of a their strategy, which is also a slight difference in traditional warfare. So really, these terrorists aren't much different than someone like Timothy McVeigh. Here's Robert Farley asking why someone like McVeigh couldn't be killed just like we killed al-Awlaki in Yemen:
The story might be different for such opponents of the government as Timothy McVeigh or John C. Breckinridge. Were capture of McVeigh deemed infeasible, and were he deemed to play a senior operational leadership role in a terrorist organization, a drone strike might just fit under Holder’s rules. Much would depend on whether the authority to order such a strike depends on Congressional authorization or is inherent to the power of the Presidency; Holder dances around this issue, although he does argue that groups not specifically affiliated with Al Qaeda (and thus not subject to the AUMF) are exempt from military commissions. Nevertheless, it is not impossible to imagine the Justice Department finding some statutory support for executive action against a suspected domestic terrorist such as McVeigh. With regards to Breckinridge, the United States obviously believed itself at war against Southern rebels, which would presumably allow the targeting of rebel leaders regardless of their status as American citizens.
I'm not familiar with the McVeigh case. But it raises the issue of whether we are at war with a specific terrorist organization like al-Qaeda, or with terrorism in general. Because if we are at war with terrorism in general (which would be ridiculous and maybe impossible), I think Holder's reasoning would extend to being able to use drones to stop an accused terrorist in the US just like they did with al-Awlaki. I somehow doubt Holder or Obama would say they have this power. To answer Farley, I think Holder wasn't clear on the point because he knows the American public would likely have a problem with it. Thus he frames it in a way that makes the issue about terrorists in foreign countries because he knows Americans don't care about the rights of foreigners, despite my efforts to convince them they should.
Back to the idea of what a war is, I don't think a "War on Terror" or a war on al-Qaeda is the same as traditional wars. I think it's a little more similar to organized crime. The main difference is that there is a political component to it. Terrorist groups like al-Qaeda have directed their attacks and rhetoric on the US as a state. So even though they aren't state actors in a traditional sense, they are attacking our state with a similar purpose that a state in a traditional war would. I think this is the strongest case the Obama administration has.
But we also treat it differently than organized crime or a case like McVeigh's because it originates in foreign countries, it's difficult to stop, and it can cause massive damage. Because of that and the purpose of al-Qaeda, I do think we can go further in extending executive power than we could if we were talking about organized crime or just plain old murder. But I think what the Obama administration proposes goes too far. We aren't at war in the same sense that we were at war with the Japanese and Germans in WWII or the British in the Revolutionary War. The very existence of our nation is not at stake, which is why the executive was given more power in those situations. Protecting the public from terrorist attacks is obviously of vital importance. But it doesn't mean we can do away with rights as if the British were on our shores and the fate of our freedom was hanging by a thread.