A consensus has grown in Washington that the next nuclear arms negotiation with Moscow should aim to limit all U.S. and Russian nuclear weapons, not just deployed strategic ones. That would raise challenging issues. Moscow may insist that it would put non-strategic weapons on the table only if Washington addresses issues of concern to Russia, particularly, missile defense.
If that is the case, the Joe Biden administration should consider whether the benefits to the United States and allied security of limiting all nuclear weapons, including non-strategic nuclear arms, would justify accepting some constraints on missile defense. There are reasons to consider such a trade-off. Refusing to discuss missile defense could mean forgoing limits on non-strategic nuclear weapons and provide an impetus to others to increase their strategic offensive forces.
Time to Cover All U.S. and Russian Warheads
The New Strategic Arms Reduction Treaty (New START) limits the United States and Russia each to no more than 1,550 deployed strategic warheads on deployed intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs), with each deployed nuclear-capable bomber attributed as one deployed warhead. New START does not limit non-deployed strategic warheads or any non-strategic nuclear warheads (deployed or non-deployed). These weapons collectively make up 60 to 65 percent of the active U.S. and Russian stockpiles.
When signing the treaty in April 2010, President Obama proposed that the next U.S.-Russia negotiation cover all their nuclear warheads. The Senate resolution of ratification for New START called on U.S. negotiators to seek to include non-strategic nuclear weapons in the next negotiation. Ten years later, the Trump administration returned to this idea.
Missile Defense and Limiting Non-Strategic Nuclear Arms
From 1972 until 2002, the Anti-Ballistic Missile (ABM) Treaty constrained U.S. and Soviet (later Russian) defenses against attack by ICBMs and SLBMs. As amended by a 1974 protocol, the ABM Treaty allowed each side no more than 100 launchers for ABM interceptors in a single deployment area. Such limits meant each side could have confidence that, even after a first strike, its retaliatory forces could overwhelm the limited ABM systems of the other side and devastate it. That was a cornerstone of mutual assured destruction.
American presidents were not always comfortable with this. Ronald Reagan launched the Strategic Defense Initiative in 1983, seeking to provide America with near-total protection against a strategic ballistic missile attack of any size. As technologies fell short, costs grew, and Congressional support wavered, U.S. ambitions became less sweeping. The George W. Bush administration adopted the objective of defending the homeland against a limited ballistic missile attack of a kind that might be mounted by a rogue state such as North Korea. In 2002, it withdrew from the ABM Treaty and developed the ground-based midcourse defense system (GMD). The first ground-based interceptors (GBIs) were deployed in 2004, more than a decade before any rogue state threat materialized. Today, forty-four GBIs are based in Alaska and California, with plans to deploy an additional twenty by the end of the decade.
Russia maintains a large and diverse arsenal of non-strategic nuclear weapons but has shown little interest in negotiating limits on those weapons. On the other hand, Russian officials have expressed great concern about U.S. missile defenses.
In October 2020, the Trump administration succeeded in getting the Russians to discuss an undefined one-year freeze on all nuclear weapons levels. However, it failed to close the deal. U.S. officials sought verification measures for the freeze, but the Russians did not agree.
If Moscow’s readiness to entertain a freeze on all nuclear weapons presaged a readiness to negotiate a verifiable agreement covering all nuclear arms with a duration of ten to fifteen years, that would be a positive development, but Russian officials have not said that. Some experts believe that Russia, having developed a number of systems to defeat U.S. missile defenses, no longer worries about U.S. missile defense capabilities and might agree to such a negotiation. However, most believe that Moscow would insist on limits on missile defense if limits were to be negotiated on all nuclear arms.
If the latter view is true, one potential cost of not limiting missile defense is that Russia will continue to refuse to negotiate on non-strategic nuclear weapons. That would leave the bulk of Russian (and U.S.) nuclear weapons unconstrained.
U.S. missile defense plans could have other effects. In order to preserve their ability to deter a nuclear attack, Russia and China seek to maintain the capability to hold targets in the United States at risk, even after absorbing a U.S. first strike. Although the GBIs may not be that effective, potential adversaries have to assume that U.S. missile interceptors in the future could be both more effective and more numerous.
The Pentagon has said that it will rely on deterrence to dissuade Russia or China from attacking the United States while it focuses its missile defenses on outpacing rogue states, such as North Korea. But Moscow and Beijing surely noticed that U.S. policy changed, not only with withdrawal from the ABM Treaty, but in expressions of policy in Congressional legislation. The 1999 Missile Defense Act set the goal of “defending the territory of the United States against limited ballistic missile attack,” while the 2017 National Defense Authorization Act said the United States would seek to “maintain and improve an effective, robust layered missile defense system capable of defending the territory of the United States and its allies against the developing and increasingly complex ballistic missile threat.” Congress subsequently dropped this language to be consistent with the Trump administration’s Missile Defense Review, which stated that missile defense aimed to protect the homeland “against rogue states’ offensive missile threats.” That change does not appear to have assuaged concerns in Moscow and Beijing.
The Russian military already has counters to the GMD. They include the Avangaard hypersonic glide vehicle, in addition to decoys, which the Soviet Union and United States developed in the 1960s. After being lofted into space, the Avangaard dives down and “glides” along the upper atmosphere, making it harder to track. It is already deployed, albeit in small numbers. In 2018, Vladimir Putin publicized other weapons systems designed to evade U.S. missile defenses.
China has modernized and modestly expanded its strategic nuclear forces in recent years. The Director of National Intelligence assessed in 2019 that Beijing’s strategic modernization program was motivated “to ensure the viability of China’s strategic deterrent by providing a second-strike capability and a way to overcome missile defenses.”
Not agreeing to constrain missile defenses could mean more than no limits on Russian non-strategic nuclear weapons. It could provide an impetus for other countries to increase the size of their strategic nuclear arsenals in order to overwhelm U.S. missile defenses. This is particularly true for China, which deploys a much smaller number of strategic warheads than Russia.
In the worst case, the United States could find itself in a situation with China (and Russia, if it left New START) similar to that with the Soviet Union in the mid-1960s. Then, the United States and Soviet Union pursued missile defenses while expanding their ICBM and SLBM forces, in part to overcome the other’s missile defenses. This action-reaction dynamic put the countries on a path of spending more and more on strategic offense and defense—with no real gain in security. They exited that path by concluding the ABM Treaty.
The current U.S. missile defense plan envisages no more than sixty-four GBIs by 2030. An agreement with Russia limiting each side to 100 or so interceptors capable of engaging ICBM and SLBM warheads would allow the U.S. military to maintain some capability to intercept North Korean ICBM warheads. It would also be low enough to assure Russia and China that they do not need an offensive build-up. The missile defense agreement could be time-limited, which almost certainly would be the case for a new U.S.-Russian nuclear arms reduction accord.
Currently, Defense Loses
One additional reason to consider constraints on missile defense is that, at present, they do not appear that effective. Intercepting an incoming ICBM or SLBM warhead poses a daunting task. The relatively small warhead travels at speeds up to six to eight kilometers per second. The GBI attempts to destroy it in space by releasing an exo-atmospheric kill vehicle that uses an infrared seeker to collide with the target. To date, GBIs have been successful in 55 percent of their highly-scripted tests against single targets. In 2019, the Missile Defense Agency canceled a program for a redesigned kill vehicle after concluding that it would not meet requirements. In 2020, it asked for proposals for building a next generation missile interceptor, which will not be available until the end of the decade.
The current forty-four GBIs offer some protection against a rogue state attack, but consider the following scenario involving a single North Korean ICBM with one warhead launched at Seattle. Assume that the GBIs perform as well as in tests, that is, that a single GBI will have a 55 percent chance of successfully destroying the warhead (some would argue that this is a generous assumption given the scripted nature of GBI tests). The U.S. government presumably would like greater than a 55 percent chance of saving a large American city from being nuked. Launching three GBIs at the warhead, assuming that each has a 55 percent chance of a successful interception, would yield a 91 percent chance of destroying the warhead.