Weighing the costs of today's defense strategy
Nevertheless, the drumbeat for more money has already started. Advocates of a bigger defense bankroll complain that regular spending (excluding the emergency appropriation) for national defense this year will amount to ''only'' 4.1 percent of the $13 trillion gross domestic product. Republican Senator James Inhofe of Oklahoma called for Secretary of Defense Donald Rumsfeld to bring Congress an extra wish list for next year, in case lawmakers want to top the military up to 4.5 percent of gross domestic product. But judging the military's needs based on the size of the economy makes no sense.
It's true that the requirements of an enterprise as vast as the US military are so complex that it is difficult to judge whether its budget seems too large, too small, or about right. So leaders and the public look for things to which they can compare it: how much is spent on other public priorities, how much other countries spend for defense, or how much the nation spent on the military in past years.
But implicit in such comparisons are two questions. The first is whether the defense budget is large enough to build, maintain, and operate a military force appropriate to the nation's place in the world and the security environment it faces. The second is whether the budget is affordable in the context of the nation's overall economy.
The first question -- whether the budget is large enough to keep the military the United States needs -- cannot be answered by looking at its size relative to the economy. Rather, it makes sense to compare this year's spending with the size of past budgets in dollar terms. In dollar terms and after adjusting for inflation, this year's defense outlays will make the Vietnam War or the Reagan military buildup look like small potatoes.
Even without the costs of the war, defense spending this year is far higher than it was on average during the Cold War. In other words, the nation is spending more now to keep a military that is about one-third smaller than it was during the Cold War and that faces threats from militaries and enemy networks that are clever but not nearly as large, powerful, or well equipped as those of the old Soviet Union.
On the other hand, to judge whether the defense budget is affordable, it makes sense to ask how it compares with the overall economy that supports it. Indeed, national defense spending this year will be a smaller share of the economy than the 7 percent of GDP the nation devoted on average to defense during the Cold War -- clearly not because defense spending has shrunk, but because the economy has grown. It is reasonable to conclude that the planned budget does not impose the same burden on the economy as it did during the Cold War.
Still, there are two reasons to worry about the affordability of President Bush's defense budget. The first is that, because of the administration's tax cuts, the nation is borrowing most of the military budget rather than paying for it out of today's tax revenues. That means that every year we add hundreds of billions of dollars to a growing national debt. The second reason is that since the mid-1960s, the nation has shifted some 4 percent of GDP -- once devoted to national defense -- to other priorities, particularly Social Security and Medicare.
Unfortunately, it has become commonplace among proponents of a larger defense budget to confuse the answers to the two questions. They often argue that the United States needs to spend a greater share of its economy on defense simply because it has done so in the past, as though one could measure how much security the nation needs according to how rich it is. But that's like saying a homeowner needs to buy a more expensive home security system every time she gets a raise in pay.
Cindy Williams is a principal research scientist in the security studies program at the Massachusetts Institute of Technology and editor of ''Filling the Ranks: Transforming the US Military Personnel System.''