But I have a different one. Even if we are "a nation at war," that doesn't necessarily tell us anything definitive. Do you follow? If not, think about some bygone wars. The Civil War and World War II posed threats to the very existence of the United States. Hundreds of thousands of Americans died fighting in both those conflicts. The whole country mobilized for victory.

Is that what "a nation at war" means?

Bu wait. In the Persian Gulf War, roughly 300 Americans died. The conflict posed no direct threat to the American homeland. Most people could go about their daily lives as if no war was going on.

Is that what being "a nation at war" means?

I suppose you're starting to see what I mean.

It is correct, as far as it goes, to observe that America was "a nation at war" during the Civil War, World War II, and the Persian Gulf War -- but the observation doesn't get us very far, does it?

Nor does it go very far as we discuss the "War on Terrorism," assuming that's a legitimate construct. What it means to be "a nation at war" right now is completely different from what it meant in 1861, 1941, and 1991. And I think that both Gelernter and McCarthy would have to agree. I presume they would object if President Obama declared martial law and suspended habeus corpus, as Abraham Lincoln did, or if he tried to round up all Muslim Americans into WWII-style internment camps. Yet they think the War on Terrorism calls for measures more extreme than they would've accepted had Bush tried to argue that they were justified by the Persian Gulf War.

Why use the construct at all?

If there is a War on Terrorism, if America is "a nation at war," because there is an enemy trying to attack us, it is nevertheless a war unlike any other in American history, and the ability to coherently file it under the "war" heading tells us very little about whether a particular diminution of privacy or civil liberties is legal or justified. Lots of civil libertarians believe that, war or not, terrorism can be adequately fought and addressed without compromising the Bill of Rights, the privacy of innocent Americans, or the checks and balances that keep government accountable. That belief is based partly on the fact that, war or not, terrorism doesn't kill very many people in America.

Ultimately, "we're at war" is a thing people say to justify a policy they support without having to show that it makes sense. Often that policy wouldn't pass muster in a traditional cost-benefit analysis.

Beware of the phrase, and the concept.