President Bush thinks it's obvious who's a terrorist and who's not. Slate's Michael Kinsley thinks it's inscrutable. I think it's not obvious but it is scrutable—though I agree with Kinsley that in this area, most people oversimplify.
Witness last Sunday's New York Times Book Review piece by Harvard government professor Michael Ignatieff in which he chastises Caleb Carr's book on terrorism for "blurring of the distinction between terror and war against civilians." By Ignatieff's lights, Carr's mistake is that he "makes no distinction between conventional, if barbaric, acts of war committed by a state army under regular command, as part of a formally declared campaign to defeat another state, and violence against civilians by nonstate actors with the aim not of military victory but of causing panic or inflicting revenge." Ignatieff says, for example, that Carr fails to recognize that although Civil War Union Gen. William Sherman used "barbarous means" against civilians in his march through Georgia, they were "in the context of a just intention," and he was "a serving officer of the United States, not an irregular, like the abolitionist John Brown, whose raids on slaveholders should properly be counted as acts of terror."
But (as Kinsley has observed) terrorism is inherently immoral, because it justifies any awful means. So to say with Ignatieff that a given act isn't terrorism because it has a just context is simply to assert, rather than argue, that it is not terrorism, and paradoxically also to accept the very paradigm of terrorism. And if causing panic is a guarantee of terrorism, then every strike at an enemy's lines of communications or successful use of propaganda should land the Pentagon in the dock. Ditto for the idea that non-terrorism requires a formally declared campaign, because the United States never formally declared war on Afghanistan. And there's less than meets the eye in Ignatieff's serving officer/irregular distinction too. The Nazi occupiers of France were serving officers and the French Resistance members were irregulars.
What Ignatieff misses is that terrorism isn't about irregular armies or the absence of declarations or causing panic; it's about attacking the other side's noncombatants utterly without concern for them or provocation from them. ("Noncombatants" marks a different class than "civilians" because the former includes military members who've surrendered or who have been incapacitated by prior attacks and excludes civilian employees at military installations and war plants.) If the killing of noncombatants is accompanied by some genuine concern for the other side's noncombatant population—as there would be if a civilian population was attacked in order to shorten the war to save lives on both sides—and if the other side had attacked your noncombatant population first, then what you have is the bloodiest possible variant of permissible war, but not terrorism.
Since on 9/11 al-Qaida demonstrated utter disregard for the U.S. noncombatant population and since the 9/11 attacks were not a response to a U.S. attack on any noncombatant population, those attacks count as terrorism.
For the Bush administration, so far, so good. But there are consequences of looking at things this way. The World Trade Center was not a legitimate military target. But the Pentagon was. What made the 9/11 attack on the Pentagon terrorism wasn't the target, it was the means of attacking it—which was a manifestly wanton and gratuitous attack on noncombatants. I don't mean the civilian employees of the Pentagon—they were engaged in keeping our military effective and they were attacked at their posts. I mean the clearly innocent passengers on the hijacked plane used in the attack. But if al-Qaida had attacked the Pentagon not with airliners full of innocents, but with a truck bomb driven by suicidal jihadists, that would have been war, not terrorism.
By the same token, the al-Qaida attacks on the Khobar Towers barracks in Saudi Arabia in 1996 and on the USS Cole in Yemen in 2000—because they focused on purely military targets without intentionally endangering civilians—were horrible, but not terrorism. And yes, theseattackswere sneaky, but so what? War is not fencing, where the rules require the prior issuance of an "En Garde!" If there were such a requirement, then for instance the nighttime U.S. special ops raids last October on a Taliban airbase and on a Mullah Omar compound were terrorism too, since our troops attacked without warning.
Let's face it: We cannot define terrorism so that only the other side's military can be destroyed or so that only our weapons can be used.