As the National Commission on Fiscal Responsibility and Reform goes about its business of searching for coins in the national sofa and other ways of making budgetary ends meet, I hope that the commission and those who will take action on its work will heed a letter delivered to it last week and signed by 48 scholars and practitioners of national security policy, myself included. The subject is military spending, and the need to reduce it. One can find elsewhere many specific ideas for savings in the defense budget; Benjamin Friedman (who also signed the letter) has offered some such ideas in these spaces. The letter deals more with general principles, one of which is that savings found in the Pentagon should not just be used to facilitate other uses of the funds inside the Department of Defense. That would provide no help in addressing the larger problem of the deficit.

Another principle is that the nation’s economic strength is a foundation of national security. This is true, among other reasons, because spending on defense and the military ultimately rests on the civilian economy. It is true as well because many other aspects of how the United States interacts with, and gains respect and influence in, the rest of the world rest on economic strength as well. Anything that impedes work on curtailing the deficit undermines that strength.

The letter also provides some necessary context in assessing defense spending, regarding both the budgetary input and the military capacity output. The real increase in military spending over the past dozen years—including the costs of ongoing wars, which have been put into supplemental appropriations as if they weren’t really military spending—has been 95 percent. This has helped to buy a magnificent military capability. Secretary of Defense Gates has noted, for example, that the U.S. Navy is today as capable as the next 13 navies combined. But a surplus margin of superiority does not buy increased national security.

The political and perceptual barrier to more sensible budgetary decisions that take account of these principles is the idea—reflected in the Obama administration’s decision to date to exempt the Department of Defense from budget cuts—that military spending is to be treated differently from other sectors of the budget because national security is the most important, least dispensable, function of government. National security is indeed that, but military capability is not the same as national security. Neither are military operations. National security depends less on how much military capacity we buy than on the wisdom with which we use the capacity we have.