In this year's presidential debates, George Bush and John Kerry have touted new defense and domestic spending programs -- at the same time they blithely promised to cut the federal budget deficit in half over the next four years. Even an electorate made dizzy by debates and attack ads can figure out that the numbers don't add up.

As the frustrated moderator of Friday night's debate, ABC's Charles Gibson, sputtered at one point after the candidates had ducked a question about their fuzzy math: "I have heard you both say during the campaign -- I just heard you say it -- that you're going to cut the deficit by a half in four years. But I didn't hear one thing in the last 31/2 minutes that would indicate how either one of you do that."

If the candidates are serious about cutting the deficit while the nation fights a costly war, the place to start looking, paradoxically, is the defense budget. In wartime, the defense budget is even more of a sacred cow than usual, but that shouldn't be. What's sacred is spending the money to protect troops and achieve victory in this war. But the United States is still spending billions for weapons systems that were conceived to fight an adversary that has already been defeated -- the Soviet Union.

These Cold War legacy systems are nifty weapons, beloved by the military and its boosters in Congress, and some would be nice to have -- if the country could afford them. But we can't right now. The United States finds itself in another war, where we're having trouble giving the troops in Iraq enough armored Humvees. At a time of severe fiscal problems, these gold-plated systems are a luxury.

What weapons are we talking about? My list is drawn from studies that have been done by veteran defense analysts Lawrence Korb of the Center for American Progress, Michael O'Hanlon of the Brookings Institution, and Steven Kosiak of the Center for Strategic and Budgetary Assessments. While they don't all agree on my hit list, these analysts are encouraging the kind of skeptical review of defense spending the country needs. In the analysis that follows, the numbers are drawn from Korb's data.

A starting point for defense budget skeptics is national missile defense. The Bush administration plans to spend $10.7 billion this year in a rush to deploy a system that even some of its own experts say isn't ready. That spending could be cut in half, to allow the testing for a system that would eventually work against potential adversaries such as North Korea or Iran.

Budget cutters will have a sense of "deja vu all over again" when they consider the Marine Corps' V-22 Osprey, an accident-prone helicopter that costs $100 million apiece. Even Dick Cheney tried to kill this one when he was defense secretary in the early 1990s, but it survived thanks to Congress's potent (if absurd) "Tilt-Rotor Caucus."

The country is also pouring billions into developing two very expensive fighter planes, the F-22 Raptor and the Joint Strike Fighter. Air Force officers are rapturous about the Raptor, but at an estimated cost of nearly $300 million per plane for the 200 F-22s the administration currently plans to buy, it's too expensive. The Joint Strike Fighter will cost less than a third as much -- about $70 million to $80 million each for the estimated 2,000 that will be built for the Air Force and the Navy as well as other countries. Stopping production of the F-22 will save at least $5 billion a year.

Perhaps the craziest Pentagon spending plan is to purchase 30 new Virginia-class attack submarines, at a cost of (this is not a misprint) $2 billion each. The United States already has the best attack subs in the world -- those of the Los Angeles class. What's the threat that these $2 billion subs are needed to combat? Cutting the program would save $2 billion to $3 billion annually.

Then there's the ultimate legacy system -- America's vast nuclear arsenal. The Pentagon is spending $7.8 billion to maintain 6,000 strategic nuclear weapons and delivery systems, including 800 targeted on the Soviet Union -- oops, I mean, Russia. Why keep all these weapons at a time when the country can't afford and doesn't need them?

It would be nice if these defense cuts could help balance the budget, but the truth is that they'll be needed just to keep the deficit from ballooning even further. Would it really be political suicide if the candidates began talking to American voters as if they were adults, rather than children in a candy store? Leadership is about making choices, and that includes the defense budget -- especially in wartime.