Executive Summary

• The U.S.-Russia Strategic Stability Dialogue, agreed by presidents Joseph Biden and Vladimir Putin at their June 2021 summit, has begun. It presumably is addressing the range of issues affecting strategic stability, including reductions in and limits on strategic offensive nuclear forces as well as questions related to missile defense. 
• Three phases have defined the history of missile defense: the era of unrestrained offense-defense competition prior to the negotiation of the 1972 Anti-Ballistic Missile (ABM) Treaty; the period of arms control between 1972 and 2002, during which both defenses and strategic offensive forces were limited; and the current era of unrestrained defenses and controlled strategic offensive forces, from 2002 to the present. 
• After more than six decades of missile defense investments, strategic offensive forces retain a significant and enduring edge over defensive systems. While progress has been made in defending against shorter-range ballistic missiles and their warheads (which travel at considerably lower velocities than strategic ballistic missile warheads), at no point during any of the three periods has the United States or the Soviet Union/Russia been able to produce a defensive system that has held any short- or medium-term prospect of negating the strategic offensive forces of the other, either on its own or in combination with a counterforce first strike.
• The concerted effort since 2002 by Washington and NATO to develop their missile defense capabilities against the long-range ballistic missile threats posed by North Korea and Iran has enjoyed only limited success, and the viability of the U.S. homeland defense against Pyongyang’s relatively small and unsophisticated nuclear arsenal is still doubtful. Russia’s incremental improvements to its defensive system around Moscow do not pose a significant threat to the U.S. strategic nuclear capability. 
• Nevertheless, the prospect of longer-term improvements to U.S. and Russian missile defenses continues to be a source of uncertainty that exercises considerable influence on the force sizing and development of new capabilities, particularly for Russia and the European nuclear powers, France and the United Kingdom. The limited available evidence suggests that China shares similar concerns regarding the viability of its deterrent against new defensive systems. Russian and Chinese planners appear to fear a future U.S. counterforce attack conducted primarily, or even solely, with advanced, high-precision conventional weapons that would disable a major portion of their strategic forces, leaving the remainder to have to penetrate U.S. missile defenses. 
• For Russia, the prospective long-term threat to its forces posed by the improvement in U.S. defenses and nuclear and conventional counterforce capabilities has prompted it to develop new “exotic” systems designed to ensure its retaliatory capacity, including the Avangard boostglide vehicle, the Poseidon long-range nuclear uncrewed underwater vehicle (UUV) and the Burevestnik nuclearpowered cruise missile. Russia has also expressed significant reservations about further cuts to its strategic offensive forces through arms control, if missile defenses remain unconstrained.
• France and the United Kingdom have been historically far more sensitive to developments in the Moscow ABM system given their smaller and less technologically advanced nuclear arsenals. Both powers have continued to ensure the long-term viability of their deterrents against prospective Russian improvements through the introduction of improved warheads (France) and planned increases in maximum stockpile size (UK).
• China’s smaller arsenal means that Beijing may be even more sensitive to developments in U.S. missile defense policy than Moscow. China’s recent apparent expansion of the number of its intercontinental ballistic missile (ICBM) silos may in part stem from anxieties regarding the viability of its deterrent against prospective U.S. missile defenses, although the motivation for and extent of an expanded ICBM force are still unclear at the time of writing.
• Thus, the current era of unrestrained missile defenses since 2002 has seen the deployment of defensive systems of limited short- and medium-term technical potential, combined with considerable anxiety from four of the five recognized nuclear powers that longer-term technological developments may pose a risk to their forces, stimulating their qualitative and quantitative augmentation. This has resulted in a paradox: even as they remain broadly ineffective against all but the most limited threats, strategic missile defenses nevertheless exert a destabilizing influence on the global nuclear balance.¹ 
• A number of measures, primarily between the United States and Russia, could help to limit the uncertainty over future missile defense capabilities by placing more explicit restraints on today’s limited missile defenses so that they cannot expand into systems that could put the retaliatory capability of any of the five nuclear powers at risk.
• These steps could include confidencebuilding measures, such as transparency agreements and reciprocal observation of missile defense interceptor tests, a ban on space-based missile defense interceptors, clearer unilateral explications of the extent and limits of both Washington and Moscow’s missile defense plans, as well as negotiated limits on missile defenses on either a legally or politically binding basis.
• Given their long-standing interest in missile defenses designed to counter only limited threats and the risks that an offense-defense competition could pose both to stability in the North Atlantic area and the viability of European members’ nuclear arsenals, U.S. NATO allies should do all they can to support these efforts.

Read the rest at The Deep Cuts Commission

Look up! The ghosts of space weapons past have once again darkened our cosmic doorway. Recently Britain’s Financial Times reported that China flight-tested a new breed of space weapon when it launched a massive “Long March” rocket tipped with a nuclear-capable, hypersonic glider. The missile briefly entered orbit before descending on its target, which it missed by roughly two dozen miles. The report suggested that the test was evidence that China has “made astounding progress on hypersonic weapons and [is] far more advanced than US officials realised.”

Read the rest at The Washington Post

Editor’s note: In late September, the National Interest organized a symposium on nuclear policy, nonproliferation, and arms control under the Biden administration. A variety of scholars were asked the following question: “Should Joe Biden seize the opportunity of his administration’s Nuclear Posture Review to redefine the role of nuclear weapons in U.S. security planning? How should U.S. policy change to address the proliferation threats that the United States is facing?” The following article is one of their responses:

President Joe Biden should use the opportunity of the Nuclear Posture Review (NPR) to reduce the role of nuclear weapons in the United States’ security policy and support a forward-looking arms control approach while maintaining a safe, secure, and effective nuclear deterrent. He will have to make his views known if he wants the process to produce bold options for his consideration.

First, the NPR is the ideal place to consider the planned strategic modernization program. The Congressional Budget Office estimates the program’s cost over the next ten years at $634 billion.  Maintaining a safe, secure, and effective deterrent requires that certain programs proceed, including command and control updates, the Columbia-class ballistic missile submarine, the B-21 bomber, and the B61-12 bomb. However, some programs should be reconsidered. For example, while the United States should maintain a triad that includes an intercontinental ballistic missile (ICBM) leg, the NPR should assess whether it is necessary to deploy four hundred ICBMs. It should also take an unbiased look at whether some portion of the Minuteman III force could be life-extended, allowing the Defense Department to push out to the future the question of building an expensive new ICBM. 

Pursuing all of these strategic programs would entail significant opportunity costs as less money would be available for conventional forces such as Virginia-class attack submarines, conventionally-armed missiles, and fighter aircraft. That matters. The most likely path to a nuclear exchange between the United States and Russia or the United States and China is a conventional conflict that escalates into a nuclear conflict. American conventional military power that can deter conventional conflict with peer competitors in the first place will also greatly reduce the likelihood of nuclear conflict.  

Second, the NPR will provide the basis for Washington’s approach in possible negotiations with Russia regarding further reductions and limitations on nuclear arms. American officials have said that the Biden administration would seek a limit covering all American and Russian nuclear arms. The NPR should set a level for American negotiators. How about 2,500 total nuclear warheads, with a sub-limit of 1,000 deployed strategic warheads? That would require significant cuts by the United States and Russia but would still leave both with many more nuclear weapons than any other country. Such a reduction would position Washington and Moscow to effectively press China to moderate its nuclear plans. 

Moscow will likely not agree to any nuclear reduction, let alone a limit of 2,500, unless Washington addresses issues such as missile defense. With this in mind, decisions in the NPR should account for decisions regarding other non-nuclear weapon programs, and vice versa. 

Third, Biden has endorsed moving to a declaratory policy in which the sole purpose of the United States’ nuclear weapons would be to deter a nuclear attack on the United States or an ally or partner and, if necessary, retaliate for such an attack. Both Washington and Moscow now appear to believe the other is lowering the threshold for nuclear use. That should leave no one comfortable. Adopting a sole-purpose policy would signal a different approach from the United States. 

Critics of a sole-purpose policy argue that the ambiguity in America’s current declaratory policy means that the implicit threat of the first use of nuclear weapons can help deter a conventional attack. That is a serious point, but it is almost impossible to conceive of circumstances in which an American president would authorize first use, particularly against a nuclear-armed adversary that could strike back with its own nuclear arms. Moreover, given the effort that China and Russia are devoting to developing their conventional forces, Beijing and Moscow certainly seem to believe in the possibility of great power conventional conflict, regardless of the United States’ nuclear deterrent. 

The adoption of a sole-purpose policy will require consultation with allies who depend on the United States’ extended nuclear deterrent. Those consultations may prove difficult, but there are offsets (for example, American boots on the ground) that could replace a dubious threat of first use. 

Right-sizing the United States’ nuclear forces (in part to free up funds for conventional forces), shaping a proposal for significant reductions with Russia, and adopting a sole purpose policy offer outcomes that a forward-looking NPR could advance. The review should offer these as options for the president’s consideration. He can then decide how bold he wishes to be. 

Steven Pifer is a William J. Perry Fellow at Stanford’s Center for International Security and Cooperation.

Originally for The National Interest