Mutual Assured Destruction Versus Missile Defense, the Debate Never Ended

Imagine a homeowner whose security plan is a sign on the lawn. The sign reads: "If you break in and hurt my family, my family has arranged for yours to be hurt just as badly." No locks. No alarm. No fence. The plan, he explains to the neighbors, is stable, because any burglar can see it would be a terrible trade.

That, in a driveway, is the doctrine of mutual assured destruction. It has an acronym that fits it exactly, MAD, and for half a century it was the official foundation of the nuclear balance. The question is whether a free people should accept, as a permanent principle, that its own citizens must be left defenseless on purpose. Conservatives have said no, for good reasons, and the argument has not gone away.

Two doctrines, defined

Mutual assured destruction is the idea that peace between nuclear powers is kept by each side's certain ability to destroy the other in retaliation after absorbing a first strike. Neither side can win, so neither will start. The logic requires that both sides stay vulnerable. A leader who could defend his cities might believe he could survive a war, and so a defense, on this view, is destabilizing.

Missile defense is the opposite wager: that a nation can build systems to detect, track and destroy incoming missiles, and that doing so protects people and strengthens deterrence by denying an attacker confidence that his strike will succeed. The designs range from short-range systems that shoot down rockets over a city to long-range interceptors meant for a limited attack by a small or middle power.

The two doctrines are not mirror images. MAD is a theory about stability among large arsenals. Missile defense, as practiced, is mostly about limited threats, such as a rogue state's handful of missiles or an accidental launch. Much of the fighting between them comes from confusing the two.

The history in order

The Cold War's first missile defenses were modest. The United States built the Nike family of air-defense missiles in the 1950s and studied systems against long-range ballistic missiles in the 1960s. Defense Secretary Robert McNamara moved American doctrine toward what he called assured destruction, the ability to inflict unacceptable damage on the Soviet Union after absorbing a strike, and the academic literature developed the stability argument for leaving cities exposed.

The key date is May 26, 1972, when President Nixon and General Secretary Brezhnev signed the Anti-Ballistic Missile Treaty in Moscow. Each side agreed to limit its defenses to two sites, and a 1974 protocol cut that to one. The treaty was ratified by the Senate in August 1972, in a lopsided vote. Under it, a nation promised not to build the thing that could protect its citizens, which is an unusual promise to make.

The United States used its single site, the Safeguard complex near Grand Forks, North Dakota, to protect missile fields. It became fully operational in October 1975, Congress moved to close it that same year, and it was shut down in February 1976. It had cost billions and was judged not worth keeping against the growing number of Soviet warheads. The one American defense permitted by the treaty lasted months.

In March 1983, President Reagan announced the Strategic Defense Initiative. He proposed to make nuclear weapons, in his words, "impotent and obsolete" in the long run, and asked whether it would not be better to save lives than to avenge them. Critics mocked the program with a nickname borrowed from a movie. The research that followed produced advances in sensors, interceptors and computing, and Soviet leaders took the program seriously enough to complain about it for years. Whether SDI helped to push the Soviet system toward collapse is a debated point among historians. What is not debated is that the Soviets feared a technological competition they could not win.

The 1990s saw the argument shift to threats from smaller states. The National Missile Defense Act of 1999 was signed by President Clinton, and it declared it the policy of the United States to deploy an effective national missile defense as soon as technologically possible. Then, on December 13, 2001, President George W. Bush gave Russia the six months' notice the ABM Treaty required, and the withdrawal took effect in June 2002. The sky did not fall. Russia protested and did not respond with a new arms race against the defense, and the American program went forward.

What exists now

Three systems illustrate the range, and I will describe each in general terms only.

1. Ground-based midcourse defense. Interceptors based at Fort Greely, Alaska, and at Vandenberg, California, are designed to destroy a limited number of long-range missiles in space, during the middle of their flight. Interceptors have been fielded at both sites. The system is meant for a small attack, not a Russian or Chinese barrage, and it has had a mixed test record that is on the public record for anyone to check.
2. Aegis ballistic missile defense. Navy cruisers and destroyers carry radar and interceptors, including the SM-3, that can engage short- and medium-range missiles. The ships can move to where the threat is, which a fixed site cannot.
3. Iron Dome. Israel's short-range system, developed by Rafael and Israel Aerospace Industries with American funding support for later batteries, is designed to intercept rockets and shells headed for populated areas. It was declared operational in March 2011. It is the clearest example of a defense designed for the moral purpose conservatives have in mind: keeping civilians alive while the shooting is going on.

None of these systems can stop an all-out attack by a power with thousands of warheads. That is a fact the critics emphasize, and they are right to. But it is not an argument against what the systems can do.

The two doctrines side by side

The table is meant to be fair, and it points to the central fact: these are not rival technologies, but rival answers to a moral question. What does a government owe its people if the worst happens?

The case for the defense, in numbered form

1. A government's first duty is to defend its people. The Preamble to the Constitution lists "provide for the common defence" among the purposes of the Union, and the Declaration says governments are instituted to secure the people's rights, beginning with life. A doctrine that holds the population hostage as a matter of policy reverses that order.
2. Deterrence can fail, and a defense is what remains. MAD works if every leader is rational, every launch order is deliberate, every system is secure and every crisis is understood. Those are a lot of ifs. Accidents, miscalculations and unstable regimes are the ordinary material of history. If deterrence fails, a defense turns a catastrophe into a lesser catastrophe.
3. Not every threat is a superpower. A regime with a few missiles and a willingness to gamble may not respond to the logic of mutual destruction, which assumes that a leader values his own survival and the survival of his regime above his ideological goals. A limited defense gives an American president a choice other than surrender or annihilation.
4. Defense strengthens deterrence. An adversary who is unsure that his missiles will reach their targets has less reason to strike. The argument that defense destabilizes assumes that the defender will use it to launch a first strike behind a shield. A defense limited in capacity cannot do that, and a president who wanted a first strike would not need to explain it.
5. The technology has matured. The skeptics of 1972 were reasoning about a world of vacuum tubes and primitive radar. Systems that can hit a bullet with a bullet, which is a fair description of what they do, have been tested and used in combat in some forms. The question is no longer whether it can be done, but how well and at what cost.

The steelman: why arms controllers say defenses destabilize

The best argument against defense deserves to be stated in its own terms.

Arms-control scholars say, first, that offense is cheaper than defense. It costs less to add warheads and decoys than to add interceptors, so a defense merely buys the other side a reason to build more. Second, a defense, even if limited, might look to an adversary like the first half of a plan to strike first and absorb the retaliation with a shield, and so push him to build more or to adopt a hair-trigger posture. Third, the ABM Treaty gave both sides confidence that neither would try to escape the balance, and that confidence helped to produce the arms reductions of the late Cold War. Fourth, the money would be better spent on conventional forces or diplomacy.

This is a serious case. In the 1960s and 1970s it persuaded a Republican president and a Democratic Senate. I will answer it point by point.

1. The cost-exchange argument assumes the goal is to stop everything. Against a limited threat, a defense does not need to be perfect. It needs to make the attack's success uncertain and to leave the president with options. A defense that can handle ten missiles is not defeated by a strategy of building a thousand, because the thousand are a different problem, handled by deterrence.
2. The first-strike worry applies to large defenses against large arsenals. For the defenses actually deployed, which are built for small attacks, no sane adversary imagines a shield behind which America could absorb a retaliatory blow from a major power. The worry does not describe Iron Dome, and it does not describe interceptors in Alaska.
3. Arms reductions came with the treaty, and they came with defense programs too. The START agreements of the 1990s and the 2002 Moscow Treaty on strategic reductions were negotiated after the Strategic Defense Initiative and, in the case of the latter, in the same year as the American withdrawal from the ABM Treaty. The claim that defenses prevent reductions is hard to square with the record.
4. Treaties between rivals bind only while both sides wish to keep them. The ABM Treaty permitted withdrawal on six months' notice, and its own authors expected that it might happen. A treaty that must be kept for the sake of a theory, whatever the world is doing, is not much of a treaty.
5. Spending on defense is not a substitute for diplomacy, and diplomacy is not a substitute for defense. The real alternative to missile defense is not a cheaper peace. It is an exposed population and a presidential choice between giving in and escalating.

The Founding and the moral anchor

Conservatives sometimes argue the point purely on the technology, which is the weaker ground. The stronger ground is moral. The Founders thought a government exists to secure the people's safety. The Declaration of Independence names the right to life first among the unalienable rights, and says that governments are instituted "to secure these rights." The Constitution's Preamble gives "the common defence" as one of its stated purposes. It is hard to square those words with a doctrine that says the government must make sure its people cannot be protected from a missile.

There is also a deeper tradition in the Western moral inheritance, the just-war tradition, which asks that force be proportionate and discriminate. A doctrine built on the deliberate targeting of civilian populations as a deterrent, however sincere, sits uneasily with that tradition. Leaders in the Cold War accepted MAD as the lesser evil because they saw no better alternative. When a better alternative exists, the burden of proof flips. The defenders of exposure are the ones who must show why we should not protect our own.

What the debate teaches

First, we should be modest about what defense can do. No system now deployed offers protection against a major nuclear power's full arsenal, and anyone who tells you otherwise is selling something. The deterrent forces, including the submarines described in Admiral Rickover Built the Navy That Made Nuclear Deterrence Survivable, remain the foundation, and they must be kept credible.

Second, we should be firm about what defense is for. It is for the rogue launch, the limited attack, the accident, and the case in which a leader is not deterred by the logic of destruction. For those, a defense is the difference between a decision and a disaster.

Third, we should insist that defenses be tested honestly and funded with accountability. The record of missile defense includes failed tests, cost overruns and promises that outran engineering, and the right response is oversight and not surrender. The money is the taxpayers', and Congress controls it. See The Pentagon Has Never Passed an Audit, and Conservatives Should Mind for the general problem.

The wider argument over whether strength keeps the peace is made in Deterrence Fails When an Enemy Thinks You Will Not Pay the Price. For the treaty that showed arms control working when America held strong cards, see The INF Treaty Proved Arms Control Works Only When You Hold Cards.

The case in brief

1. Mutual assured destruction keeps the peace among great powers by leaving civilians exposed on purpose, and it provides nothing if deterrence fails.
2. The 1972 ABM Treaty codified that exposure, the Safeguard site in North Dakota lasted only months, and the United States gave notice of withdrawal in December 2001, effective June 2002.
3. Today's systems, ground-based midcourse defense, Aegis and Iron Dome as a model, are built for limited threats, not for a barrage from a major power.
4. The arms controllers' best arguments, cost-exchange and first-strike fear, apply to large defenses against large arsenals, not to limited ones.
5. A government's first duty is to protect its citizens, so the burden lies on those who would leave them undefended.

What you can do: look up the missile defense lines in the latest defense appropriations bill on Congress.gov, and ask your representative, using the my-representatives page, what the program is meant to protect and how it is tested.