Credible Strategic Deterrence Requires A Land-Based Missile Component

The future of the intercontinental ballistic missile (ICBM) leg of the nuclear Triad is again subject to debate. On the one hand, a recent study by Global Zero called for steep reductions in the U.S. nuclear arsenal, including elimination of the entire land-based component. Under this plan, the nation’s nuclear deterrent would be reduced to a handful of missile-carrying submarines at two ports and a few nuclear-capable bombers deployed to a single airfield. On the other hand, the Air Force Requirements Oversight Council has just released the first formal planning document calling for a new ICBM that would be deployed starting in 2030. In addition to the development of advanced guidance and propulsion technologies, the Air Force document calls for consideration of alternative basing modes for the future long-range system.

It might seem anachronistic to some that the Pentagon would consider a new ICBM. Even if the United States needs to maintain a strategic deterrent, why not just put it all on ballistic missile submarines and send them to sea? If we need flexibility, there is the strategic bomber force.

The reason to maintain a land-based component in the strategic nuclear force goes to the essence of how deterrence operates. Deterrence works when any nuclear aggressor, regardless of circumstances, is denied the prospect of being able to commit aggression without the certainty of devastating retaliation. Essential to our ability to impose this “understanding” on a prospective adversary is to ensure that he cannot find a way of avoiding that retaliation. Since the U.S. first deployed strategic nuclear forces, they have been postured in such a manner so as to make it clear to anyone thinking of employing nuclear weapons that they cannot avoid the certainty of retaliation by attempting a surprise attack or a cheap shot against vulnerable elements of the Triad. The most effective strategic deterrent is one in which the aggressor actually is left in a weakened state by virtue of his attempt to finesse the threat of retaliation.

This is where the land-based component of the Triad comes into play. Should an enemy attempt a limited nuclear strike against targets in the homeland, forces abroad or U.S. allies, ICBMs provide a potent and credible retaliatory capability. The ICBM force allows the National Command Authority options to move in a controlled manner up the escalation ladder. At the same time, the presence of hundreds of ICBMs on U.S. soil means that any aggressor seeking to limit U.S. nuclear retaliation must launch a massive preemptive attack on this country which would guarantee retaliation in kind. In fact, unlike the case with naval bases or airfields, in order to have high confidence of success in such an attack, two or more warheads are needed for each hardened ICBM silo. This virtually guarantees that an attacker disarms himself in the attempt.

There are other important reasons to maintain an ICBM force. On a per warhead basis land-based missiles are the lowest cost way of maintaining a deterrent. They are in many ways also the most effective and secure, being invulnerable to such countermeasures as air defenses or anti-submarine warfare. They do not require provisioning or refueling as do the other components of the Triad.