Nunn's Right—Let's Defend

Sen. Sam Nunn (Ga.) recently broke ranks with his fellow Democrats and endorsed the idea of defenses against an accidental or unauthorized nuclear attack.

Despite polls regularly showing that large majorities of Americans favor defenses, Nunn was quickly attacked—by both liberals and conservatives.

Liberals denounce the senator for departing from the arms-control orthodoxy, which holds the ABM Treaty as sacred writ and sees any amount of defense as upsetting the balance of terror. And indeed, Nunn recognizes that even a very limited defense will have to involve space-based components to be effective—and that violates the ABM Treaty.

Conservative critics argue that Nunn's plan is too limited to do any good, even as a first step. They generally confuse his proposal with a more limited plan developed by Reps. Les Aspin (D–Wisc.) and John Spratt (D–S.C.). It would deploy only 100 ground-based interceptors at a single site, as allowed by the ABM Treaty. National Review correctly notes that this scheme could not protect either coast from submarine-launched attacks of even a single missile.

That's because a ground-based defense is limited to a specific "footprint." Even if the defense is located at the most important targets, there is no guarantee that an accidental or unauthorized launch would be aimed at those particular spots.

But ground-based defense, by itself, suffers from a more fundamental limitation. It can only attack warheads in their final stages of flight. By contrast, a space-based defense has the potential of blasting the ICBMs or SLBMs before they have lofted their warhead buses into space.

That difference is crucial. There's enormous numerical leverage in hitting the rocket itself. A single hit of an ICBM may knock out a dozen warheads and hundreds of decoys—each of which might otherwise have to be targeted separately by the ground-based system.

Consider also the impact of such a defensive capability on Soviet attack planners. Facing only a ground-based defense, they can aim enough warheads at specific key targets to have good odds of getting past the interceptors. But with space-based defenses, even of limited effectiveness, the Soviets have no way of knowing which warheads will get through. They would have to vastly increase the size of their arsenal, at huge expense.

Or they would have to give up ICBMs and SLBMs as their principal weapons. Which is the point of defenses, after all.

Recognizing the leverage of space-based defenses, Nunn proposes amending the ABM Treaty to permit limited space-based testing and deployment. Or we could simply follow the Soviets in ignoring it. Air Force intelligence recently concluded that they are poised to break out of the ABM Treaty. They are said to be linking up their early-warning radars with interceptor-guidance radars and mass-producing the latter, as well as new interceptor missiles. So the ABM Treaty may soon be a dead letter.

What's clear is that it must no longer be used to deny Americans the protection that our technology can now give us—at least against limited attacks.