Deterrence, but Updated: Where missile defense comes in-crucially.

The U.S. nuclear deterrent worked for 40 years against the Soviets, so why won't it work now against lesser powers, armed with drastically fewer nuclear weapons than Moscow? Once the cruder, practical arguments against a U.S. missile defense are cleared away-it simply won't work, it's too expensive, etc.-the most sophisticated and best case against a defense hangs on this argument: Nuclear deterrence worked without a missile defense for decades, making a defense now at best superfluous, at worst a destabilizing force.

This argument has been made, in various forms, by Michael Kinsley, Thomas Friedman, Robert Wright, Christopher Hitchens, and a slew of Democratic politicians. Fancier than the average soundbite, it is the Belvedere vodka of anti-missile-defense arguments. But the case for nuclear deterrence made by these new, liberal Dr. Strangeloves is shot through with misunderstandings, beginning with the fundamental question of how-and how well-deterrence actually worked against the Soviets. Deterrence essentially involves convincing a state that the costs of a given action will be higher than any potential benefits. It is not nearly as easy as it looks, especially in the post-Cold War world.

A small circle of conservative defense strategists has in recent years updated Cold War deterrence theory, and perhaps foremost in this circle is Keith Payne, a scholar who runs a small think tank called the National Institute for Public Policy. Payne has worked closely with defense analysts who now occupy the top levels of the Bush administration, and has written a new book-The Fallacies of Cold War Deterrence and a New Direction-that is an essential text for understanding the reasoning behind the administration's push for missile defense. (Asked whom to talk to about the current state of deterrence theory, one nuclear expert quipped, "If you talked to Keith Payne, you've talked to everyone.") Properly understood, deterrence is more subtle and less foolproof than the simplistic version advanced by Kinsley & Co., and certainly requires a missile defense to bolster it.

Opponents of missile defense misunderstand the purpose of the U.S. nuclear deterrent in the Cold War at the most basic level. As former CIA director Jim Woolsey has written in NR (June 19, 2000), the deterrent was never primarily to dissuade the Soviet Union from launching a city-busting, out-of-the-blue nuclear strike against America (although that was important). It was meant to deter a conventional attack against Western Europe. The West didn't have the conventional arms to oppose such an attack on the ground, so the United States always let the possibility of its first-use of nuclear weapons hang in the air, a not-so-subtle way to discourage the Soviets from rolling their armor across the Fulda Gap.

The problem for the U.S. in today's international environment is precisely that its deterrence policy did work in the Cold War. It demonstrated that a nuclear force can make the potential costs of war too high even for an adversary who possesses an overwhelming conventional advantage. Today, the Fulda Gap is much less important than simply The Gap, and it is the U.S. that may need to project an overwhelming conventional power, probably in the Middle East and Asia. The nuclear deterrence that worked against the Soviets can now readily be turned against the United States. Is America, as Keith Payne asks, willing to absorb greater costs-perhaps entire cities destroyed-than the Soviets? Unlikely. Will the stakes in a foreseeable crisis be higher for the U.S. than they were for the Soviets? Unlikely again, since the Soviet Union was contending over the fate of Europe, while the United States may be contending over the fate of Taiwan.

Some missile-defense critics acknowledge that the U.S. will be deterred by new nuclear states. "The possession of nukes would probably give a dictator more leeway in world affairs, [and] great powers might be less inclined to confront such a dictator," wrote Robert Wright, a dogged opponent of missile defense, recently in Slate. This is precisely the effect that the United States has to fear in the post-Cold War world, and its massive nuclear force is powerless to counter it. In fact, the size and structure of the force probably never had quite the importance attributed to it. Arms-controllers during the Cold War obsessed over tiny adjustments in the U.S. and Soviet missile forces, and deterrence became mostly about number-crunching game theory-Gradgrind does nuclear weapons.

As Payne points out, this niggling over the specific mix of weapons was a luxury, possible only because the strategic situation with the Soviets was fairly stable. The Soviets were a revolutionary power, but generally showed little taste for provoking a major war and had a bureaucratic power structure and a decision-making process that we understood fairly well. So, deterrence theorists assumed away all the really nettlesome questions about the Soviets, about their goals, their ideology, their culture. Cold War theorists, Payne writes, "derived grand conclusions about deterrence based on the one factor that is relatively easily measured, i.e., the balance of nuclear forces." Not every U.S. adversary for all time will be as well understood, or as predictable.

Why, missile-defense critics counter, would Kim Jong Il be any less rational than Brezhnev? But rationality is not the point. Payne makes an important distinction between rationality and reasonableness. Rationality is a tool that allows someone to figure out how to maximize a certain value. Reasonableness involves his ultimate goals and system of values. Almost all leaders are rational. The mistake is to assume that therefore all leaders must accept Western premises and behave "reasonably"-in other words, the way we ourselves would behave. This fallacy is at the root of most understandings of deterrence. As the father of Cold War deterrence theory, Thomas Schelling, put it, "You can sit in your armchair and try to predict how people will behave by asking how you would behave if you had your wits about you. You get, free of charge, a lot of vicarious, empirical behavior."

Yes-lots of empirical evidence: about yourself. But foreign leaders can be as rational as Americans, while still being criminally unreasonable. Hitler, of course, from 1933 to 1939 calculated his way to several diplomatic victories over the West, in a monstrous cause. It also is possible-though missile-defense critics like to deny it-for an unreasonable leader to be willing to inflict terrible costs on his own country. In March 1945, Hitler gave his infamous Nero's orders, essentially calling for the destruction of Germany. After the first U.S. atomic attack on Hiroshima, the Japanese war minister said: "Would it not be wondrous for this whole nation to be destroyed like a beautiful flower?" During the Cuban missile crisis, according to a Soviet commander's later account, the Cubans "were ready for war. Maybe they believed so strongly, they were ready to sacrifice themselves. They would say, 'Cuba will perish, but socialism will win.'"

The Cuban missile crisis, Payne argues, demonstrates how close deterrence came to failing even against the Soviets. In a crisis, the communication that is so important to deterrence-to convey threats and establish thresholds-tends to break down. In 1962, the U.S. knew the proper channels through which to communicate with the Soviets, and had roughly 20 years of experience with them. But Washington still lacked crucial information, which nearly led to catastrophic errors. It did not know, for instance, that the local Russian commander in Cuba apparently had been pre-delegated to launch his missiles if attacked. So the option pushed by the Joint Chiefs of Staff-an air strike and invasion-probably would have unwittingly prompted a nuclear exchange. As Bob McNamara always says, "We lucked out." Here, then, is the ultimate backup to the sort of deterrence pushed by critics of missile defense: luck.

There is no reason to believe that luck will always hold, especially against culturally alien adversaries whom the U.S. doesn't understand as well as it did the Soviets. The U.S. knows, for instance, little or nothing about North Korea. In the recent EP-3 crisis, it didn't even know who was making decisions in China. And deterrence failed against Saddam Hussein prior to his invasion of Kuwait, partly because we didn't know how to deliver a message to him. Diplomat April Glaspie's overly subtle warning was taken as a modified go-ahead. "We foolishly did not realize he was stupid," said Glaspie afterwards. Well, get used to it-the world is full of folly and miscalculation.

Even if a deterrent is perfectly pitched to an adversary, there is no guarantee that it will work. As Payne argues, war sometimes has little to do with external factors like deterrence, but is instead driven by internal politics and assumptions that make it an imperative. Dean Acheson said in 1941: "No rational Japanese could believe an attack on us could result anything but disaster for his country." Maybe. But the Japanese felt that they only had two terrible choices: getting squeezed out of China by U.S. economic pressure, or undertaking a risky war. It's a dangerous mindset, but one hardly unheard of in international affairs. Stalin said to Mao, before China shocked the U.S. by entering the Korean War: "If a war [with the U.S.] is inevitable, then let it be waged now." If Taiwan were to declare independence, the current Chinese regime might well see that as a threat to the PRC's very survival, making any U.S. security guarantee to Taiwan seem well worth testing.

In light of all this, missile defense has a twofold role in a sound, up-to-date deterrence regime. The first is to help deter the anti-U.S. deterrent, by neutralizing the nukes of an adversary. Missile defense would represent a direct threat to a rogue state's power, by undermining its ability to intimidate the U.S. into inaction. Critics argue that blocking a rogue state's missiles would only prompt it to pursue other options, such as "suitcase bombs" sneaked into the U.S. But this is not so easy, given U.S. security precautions ("Did you pack that nuclear weapon yourself? Has it been in your possession at all times?"), and suitcases can't project power in a crisis quite the way missiles can (which is why there is a rush around the world to build ICBMs instead of luggage). The second purpose of a defense is to provide a backstop should deterrence fail, as it has many times in history, almost did in the Cold War, and inevitably will again.

Keith Payne laments that Cold War deterrence theory was built on a tautology: A rational leader will be deterred because if he's not deterred, he's irrational. Tautologies may be useful in the classroom, and also to clever op-ed writers, but ultimately U.S. national-security policy cannot depend on them.