TOO PUSILLANIMOUS A PURPOSE:

The Nukes We Need: Preserving the American Deterrent (Keir A. Lieber and Daryl G. Press, November/December 2009, Foreign Affairs)

The primary purpose of U.S. nuclear forces is to deter nuclear attacks on the United States and its allies. During peacetime, this is not a demanding mission. The chance that leaders in Beijing, Moscow, or even Pyongyang will launch a surprise nuclear attack tomorrow is vanishingly small. But peacetime deterrence is not the proper yardstick for measuring the adequacy of U.S. nuclear forces. Rather, the United States' arsenal should be designed to provide robust deterrence in the most difficult of plausible circumstances: during a conventional war against a nuclear-armed adversary.

In the coming decades, the United States may find itself facing nuclear-armed states on the battlefield. U.S. alliances span the globe, and the United States is frequently drawn into regional conflicts. Washington has launched six major military operations since the fall of the Berlin Wall: in Panama, Somalia, Kosovo, Afghanistan, and twice in Iraq. Furthermore, most of the United States' potential adversaries have developed -- or seem to be developing -- nuclear weapons. Aside from terrorism, the threats that dominate U.S. military planning come from China, North Korea, and Iran: two members of the nuclear club, and one intent on joining it.

The central problem for U.S. deterrence in the future is that even rational adversaries will have powerful incentives to introduce nuclear weapons -- that is, threaten to use them, put them on alert, test them, or even use them -- during a conventional war against the United States. If U.S. military forces begin to prevail on the battlefield, U.S. adversaries may use nuclear threats to compel a cease-fire or deny the United States access to allied military bases. Such threats might succeed in pressuring the United States to settle the conflict short of a decisive victory. [...]

To illustrate the growth in U.S. counterforce capabilities, we applied a set of simple formulas that analysts have used for decades to estimate the effectiveness of counterforce attacks. We modeled a U.S. strike on a small target set: 20 intercontinental ballistic missiles (ICBMs) in hardened silos, the approximate size of China's current long-range, silo-based missile force. The analysis compared the capabilities of a 1985 Minuteman ICBM to those of a modern Trident II submarine-launched ballistic missile.

In 1985, a single U.S. ICBM warhead had less than a 60 percent chance of destroying a typical silo. Even if four or five additional warheads were used, the cumulative odds of destroying the silo would never exceed 90 percent because of the problem of "fratricide," whereby incoming warheads destroy each other. Beyond five warheads, adding more does no good. A probability of 90 percent might sound high, but it falls far short if the goal is to completely disarm an enemy: with a 90 percent chance of destroying each target, the odds of destroying all 20 are roughly 12 percent. In 1985, then, a U.S. ICBM attack had little chance of destroying even a small enemy nuclear arsenal.

Today, a multiple-warhead attack on a single silo using a Trident II missile would have a roughly 99 percent chance of destroying it, and the probability that a barrage would destroy all 20 targets is well above 95 percent. Given the accuracy of the U.S. military's current delivery systems, the only question is target identification: silos that can be found can be destroyed. [...]

The United States' nuclear weapons are now so accurate that it can conduct successful counterforce attacks using the smallest-yield warheads in the arsenal, rather than the huge warheads that the FAS/NRDC simulation modeled. And to further reduce the fallout, the weapons can be set to detonate as airbursts, which would allow most of the radiation to dissipate in the upper atmosphere. We ran multiple HPAC scenarios against the identical target set used in the FAS/NRDC study but modeled low-yield airbursts rather than high-yield groundbursts. The fatality estimates plunged from 3-4 million to less than 700 -- a figure comparable to the number of civilians reportedly killed since 2006 in Pakistan by U.S. drone strikes.

One should be skeptical about the results of any model that depends on unpredictable factors, such as wind speed and direction. But in the scenarios we modeled, the area of lethal fallout was so small that very few civilians would have become ill or died, regardless of which way the wind blew.

Critics may cringe at this analysis. Many of them, understandably, say that nuclear weapons are -- and should remain -- unusable. But if the United States is to retain these weapons for the purpose of deterring nuclear attacks, it needs a force that gives U.S. leaders retaliatory options they might actually employ. If the only retaliatory option entails killing millions of civilians, then the U.S. deterrent will lack credibility. Giving U.S. leaders alternatives that do not target civilians is both wise and just.

A counterforce attack -- whether using conventional munitions or low- or high-yield nuclear weapons -- would be fraught with peril. Even a small possibility of a single enemy warhead's surviving such a strike would undoubtedly give any U.S. leader great pause. But in the midst of a conventional war, if an enemy were using nuclear threats or limited nuclear attacks to try to coerce the United States or its allies, these would be the capabilities that would give a U.S. president real options.

GOOD THINGS IN SMALL PACKAGES

As the United States restructures its nuclear arsenal and overall strategic posture, it should ensure that it has three distinct capabilities. First, it still needs some high-yield nuclear weapons (such as those deployed on land-based missiles and in submarines), although fewer than it currently possesses. If the U.S. military had to destroy an enemy's nuclear force in circumstances so dire that collateral damage was not a major concern, these weapons would provide the best odds of success. They maximize the odds of getting the target, albeit at the cost of enormous collateral damage.

The United States also needs conventional counterforce weapons. The U.S. military already fields precision nonnuclear weapons that can destroy nuclear targets, and the Pentagon has wisely made conventional capabilities a key element of its "global strike" mission, which seeks the capacity to hit any target anywhere in the world in less than an hour. Conventional weapons permit the United States to conduct a counterforce strike without crossing the nuclear threshold, and without killing millions.

To illustrate the promise of conventional counterforce, we modeled an attack on 20 land-based silos using B-2 bombers and bombs guided by GPS. If GPS signals were not jammed, an attack would destroy most of the silos and have about a 50-50 chance of destroying them all. The problem with conventional counterforce weapons is that, lacking the destructive power of nuclear weapons, they depend on pinpoint accuracy. If an enemy can jam GPS signals near the target, the odds of destroying all 20 silos with current bombs are essentially nil. In short, conventional weapons offer the ability to destroy an enemy's nuclear forces with minimal collateral damage, although with only a fair chance of success.

For the third leg of the U.S. strategic force, the United States should retain the lowest-yield warheads in its nuclear arsenal and (if it has not already done so) enhance their accuracy. If the low-yield nuclear bombs and cruise missiles, which reportedly use inertial guidance systems, were even half as accurate as their conventional, GPS-guided cousins, they could match the effectiveness of high-yield nuclear weapons while inflicting casualties more akin to those caused by conventional bombs.

Professor Press thinks me a lunatic, but the fundamental question here is whether that "primary purpose" of deterring an enemy attack isn't almost unjustifiable given how easily, as he and Mr. Lieber demonstrate, we could eliminate their nukes pre-emptively.

Rather than sit back and figure out ways to prevent a nuclear attack on us by our enemies in the event of war, we should use the capability outlined above to render our enemies non-nuclear to begin with. Given the evil nature of the regimes in question, we would be justified in striking without prior notice. But we could also issue them quiet ultimatums so they might save some face. The PRC would be required to surrender its weapons and North Korea and Iran to raze their facilities.

At the same time, we could let Pakistan know that while not yet an official enemy of ours, both the instability of the government there and the historic enmity against our ally India make its nukes intolerable as well.

And, while we're at it, we could tell France and Britain to give up their delusions of grandeur and give up their nukes.

India and Israel would be allowed to keep their weapons not only because they are friends but because those weapons are aimed at mutual enemies.

This leaves only Russia and it represents the most difficult case. Not difficult militarily, but difficult strategically. The fact is that Russia is no longer an enemy but not really a fried, certainly not a reliable one. It's also a dying state but one that happens to border the PRC and restive Islamic states, besides having increasingly radicalized internal Muslim populations itself. If it ever were to use its nukes, it would not be unlikely to use them on folks we'd not be oversorry to see bombed. The most brutally realistic position would be to allow them to keep their nukes just in case we want them to use the weapons. The tidier and more humane solution would be to tell them that their nuclear days are over too.

At any rate, we're awfully fond of making pronouncements like "Never Again" and raging against Chamberlain for not pre-empting Hitler or W for not stopping al Qaeda pre-911. Well. here's a perfect opportunity to show that we've learned from history and we're serious about using our power to prevent the unspeakable before it occurs. We have the means to not just end nuclear proliferation but to roll back the nuclear club to a small but trustworthy membership of Anglospheric allies. Heck, President Obama would even have earned that Nobel Peace Prize if he he removed nukes from the Axis of Evil.

Posted by Orrin Judd at October 26, 2009 6:52 AM