If American war planes are firing missiles at a foreign nation or militia, that is war. Everyone understands as much with respect to foreign countries. Imagine an Iranian drone carried out a single targeted missile strike on an Israeli settlement. Would that be an act of war? Or not so much, because it's merely part of "a balance of measures—political, military, legal, and otherwise," to degrade Zionism? What if Russia stationed, in a foreign country, just a tiny fraction of the troops that Bush mobilized for the occupations of Iraq and Afghanistan?

The Framers gave Congress the power to declare war in part because they knew that war is the health of the state. They feared that the power incentives presidents have to wage war would cause them to do so in cases when they shouldn't. They trusted a body of representatives more than the instinct of one man. And they believed that a body directly responsive to the people should have a say.

Everything about that logic applies to the decision to fight ISIS.

As I see it, Obama is waging war illegally, just like he did previously (and without legal consequences) in Libya. He has failed to secure the congressional authorization needed to be consistent with his own avowed understanding of the War Powers Resolution. That legislation passed because a bygone president was able to enmesh America in a war that, for some years, didn't seem entirely like a war.

​But say for the sake of argument that we aren't really at war, and that "in his heart of hearts," Obama doesn't believe himself to be at war. If that's so, the Obama administration has no right to take many of the actions it has justified by citing the president's war powers. Obama and his defenders can't have it both ways. If no war, then no increased powers as the commander-in-chief. In court, Obama's lawyers don't have any doubt about whether their boss considers himself to be at war as a matter of law. They don't much care what's in his heart.

Later in his piece, Ambinder hazards a guess as to why we're fighting ISIS. It's as good as any:

We are not fighting ISIS because ISIS is plotting an imminent attack on the U.S. We are fighting ISIS because (a) the U.S. does not want Iran to fight and defeat ISIS alone; (b) the Saudis recognize that ISIS poses an existential threat to them if not checked soon; (c) Obama believes the U.S. has a residual responsibility to try to help stabilize Iraq if Iraq asks for the help, which it now is; (d) ISIS, well-funded and well-armed, has threatened the United States directly, and there is no reason to think that they won't try to find some way to directly attack American interests down the road: (e) an ISIS unchecked could throw the entire region into complete chaos; (f) Syria seems to welcome the help, and in any case, the administration has signaled that airstrikes in Syria will be a very modest part of this campaign; and (g) the relative risk to American assets, people, and authority is low.

Again, using military force in foreign countries to undercut geopolitical rivals, protect allies, and preempt attacks sounds an awful lot like war, but whatever word one wants to use, shouldn't there be a national debate about whether our money and military ought to be used for those goals? Obama purports to believe that "it is always preferable to have the informed consent of Congress prior to any military action." He hasn't honored that belief or disavowed it. The ambiguity permits him to retain his greatest asset as a politician: slipperiness. He inspires in his supporters a desire to see in him whatever they want to see in him.