In the 13 years since 9/11, Americans have grown accustomed to the ambiguity of U.S. efforts to deter, disrupt, and preempt the threats posed by a shape-shifting cast of terrorist groups. The ebbs and flows of America's inexorable counterterrorism campaigns have produced a tangled web of terminology. For evidence, take a look at the many ways the New York Times homepage referred to Obama's intervention on Thursday:

New York Times

What Obama didn't quite foresee at National Defense University in 2013 was a group like ISIS, which had yet to split with al-Qaeda and seize vast tracts of territory. Instead, his vision of terrorism's future included "lethal yet less capable al Qaeda affiliates; threats to diplomatic facilities and businesses abroad; [and] homegrown extremists." The United States, he said, could not combat these actors with force alone:

We cannot use force everywhere that a radical ideology takes root; and in the absence of a strategy that reduces the wellspring of extremism, a perpetual war—through drones or Special Forces or troop deployments—will prove self-defeating, and alter our country in troubling ways.

Obama also called for the repeal of the 2001 Authorization for Use of Military Force (AUMF) against "those responsible" for the 9/11 attacks—language often interpreted as referring to al-Qaeda and its "associated forces." If America had adopted a perpetual war footing, he argued, the AUMF was the foundation on which it stood.

This week, however, perpetual war appeared to get the best of Obama. Administration officials are reportedly invoking the AUMF as a legal justification for the U.S. campaign against ISIS. As The Daily Beast's Eli Lake explains, that means, incredibly, that a resolution designed to justify attacks on al Qaeda-linked groups "would also apply to a terrorist organization that is itself at war with al Qaeda." The definition of "those responsible" for 9/11 expands and explodes. The perpetual war continues. What Obama might have called "war footing" in 2013, he described Wednesday as a "comprehensive and sustained counterterrorism strategy."

The question of whether the AUMF applies to U.S. military intervention in Iraq and Syria is part of a larger debate over whether the campaign is lawful, and whether it requires congressional authorization. But that debate, in turn, is partially a reflection of the merging of peacetime and wartime, and the resulting confusion about which legal frameworks apply to which actions.

The boundary between peace and war was already dissolving in 2002, when The West Wing aired an episode on this very phenomenon. In the scene below, Admiral Percy Fitzwallace, the joint chiefs chairman, makes the case for killing the defense minister of the fictional Middle Eastern country of Qumar, who is believed to be plotting terrorist attacks against the United States.