By Steven Pifer
President Joe Biden’s administration is conducting a missile defense review in parallel with its Nuclear Posture Review (NPR). Those reviews will determine whether to adjust the nuclear and missile defense programs that the administration inherited from its predecessor. They will also shape decisions on the contribution that negotiated arms control could make to meet the increasingly complex challenges of maintaining strategic stability and enhancing U.S. and allied security.
One question the administration should consider is whether it can design a missile defense approach that would protect the homeland against limited attacks by rogue states such as North Korea while avoiding an offense-defense dynamic that would frustrate efforts to achieve nuclear arms reductions with Russia that go beyond the 2010 New Strategic Arms Reduction Treaty (New START) or to agree on any constraints on nuclear forces with China.
The Offense-Defense Relationship
In June, the administration launched a missile defense review, which should be completed early in 2022, about the same time as the NPR. The two documents produced by the reviews should be considered in tandem.
Washington and Moscow have long recognized the interrelationship between strategic offense and defense. The Strategic Arms Limitation Talks (SALT) in 1972 produced agreements addressing both sides of the equation. The Interim Offensive Agreement constrained intercontinental ballistic missile (ICBM) and submarine-launched ballistic missile (SLBM) launchers. The Anti-Ballistic Missile (ABM) Treaty limited strategic missile interceptors and prohibited a national missile defense. The two accords were seen as enhancing strategic stability, a situation in which incentives for the United States or the Soviet Union, and later Russia, to strike first with nuclear weapons were minimized.
U.S. President Ronald Reagan took a different approach in 1983 with the Strategic Defense Initiative. He sought to defend the United States against ballistic missile attacks of any size, although the limitations of technology and cost frustrated that goal. The National Missile Defense Act of 1999 set U.S. policy so as to “deploy as soon as is technologically possible an effective National Missile Defense system capable of defending the territory of the United States against limited ballistic missile attack.”1
The George W. Bush administration withdrew from the ABM Treaty in 2002 and subsequently began deploying ground-based interceptors (GBIs) to engage strategic ballistic missile warheads. The United States maintains 44 GBIs, with plans to add 20 more by 2030. The military also deploys Standard Missile-3 (SM-3) and Terminal High Altitude Area Defense (THAAD) interceptors, which are designed to engage short- and intermediate-range ballistic missile warheads.
The Trump administration’s Missile Defense Review affirmed the idea of defending against “a limited ICBM attack” mounted by a rogue state, although the president’s comment that the U.S. goal was to “ensure we can detect and destroy any missile launched against the United States—anywhere, anytime, anyplace” suggested that he might have something more ambitious in mind.2 As for Russian and Chinese strategic ballistic missiles, the review said the United States “relies on nuclear deterrence to prevent potential Russian or Chinese nuclear attacks.” The review spelled out, however, new technologies for exploration and possible development.3 Moreover, in 2020, the Pentagon successfully tested an SM-3 interceptor against an ICBM warhead-class target as part of an effort to develop a second layer of interceptors to supplement the GBI system.
Although Russian officials regularly voice concern about U.S. missile defenses, their fears appear overstated given Russia’s large ICBM and SLBM warhead numbers. Still, the Russian military has developed systems such as the Avangard boost-glide vehicle to penetrate missile defenses. In addition, Russia maintains its own missile defense systems, including the A-135 system protecting Moscow, the S-400, and the new S-500. The latter two systems are advertised as having capabilities similar to the SM-3 and THAAD systems.
Beijing too has expressed concern about U.S. missile defenses, including their ability to negate a retaliatory strike following a U.S. attack on China’s nuclear deterrent. That concern could explain the recent Chinese test of what appears to have been a hypersonic glide vehicle mounted on a fractional orbital bombardment system.4 Such a system could approach the United States from the south, thus potentially evading U.S. missile defense radars that are oriented toward threats from the north or the Pacific and Atlantic Oceans. At least for the near term, Beijing’s concerns have a stronger base than Moscow’s, given the significantly smaller number of Chinese strategic warheads.
Offense Wins and Arms Race Concerns
With existing missile defense capabilities, offense will win the strategic offense-defense competition, a point acknowledged in September by General John Hyten, vice chairman of the Joint Chiefs of Staff, who said, “The defensive capabilities that we have been building tend to be very cost prohibitive on us.… And when our interceptor costs more than the weapon attacking us, that’s a bad place to be.”5 This echoes the argument made by U.S. negotiator Paul Nitze in 1985 that missile defenses should be judged on, among other things, whether they are cost effective at the margin.6
Current U.S. missile defenses fall short of that criterion. The cost of a GBI missile and kill vehicle is $65–75 million. Although the Pentagon says GBI systems have succeeded in 55 percent of their tests, skeptics argue that, given the scripted nature of the tests, this record likely overstates their performance. If these interceptors could replicate their test performance in a real attack, it would take three GBIs, costing $195–225 million, to have a 91 percent chance of destroying an incoming warhead. Russia, China, and North Korea could each build many additional warheads and decoys for that same amount of money.7
This calculation could change, most probably if a missile defense technology based on directed energy were to prove feasible. For the foreseeable future, however, spending heavily on existing strategic missile defenses appears a losing game. An adversary can increase the number of its strategic warheads and decoys at far less cost. Although existing U.S. strategic missile defenses may not be that effective, the other side will assume they will improve and increase in number. That will affect the adversary’s calculation of what strategic offensive force it needs to be able to absorb a first strike and overcome U.S. missile defenses to inflict a powerful retaliatory blow.
If missile defenses remain unconstrained and grow in number, the other side may conclude that it must expand its strategic offensive forces. This may well be a factor behind China’s apparent effort to increase its strategic nuclear forces. Russian military planners, facing questions about the future of U.S. missile defenses, might question whether Russia can afford reductions below New START’s limits. The situation could devolve into something similar to the competition between the United States and Soviet Union in the 1960s with both sides increasing ICBM and SLBM forces in part to have confidence in defeating the other’s developing strategic missile defenses. In the worst case, Washington might find itself in offense-defense races with both Russia and China.
Missile Defense Review
The Biden administration’s Missile Defense Review should address several questions. First, should the objective of U.S. missile defense policy remain protecting against a limited ballistic missile attack on the United States? If so, are specific programs unnecessary for that goal, or do they suggest to potential adversaries a desire to defend against larger-scale attacks?
Looking out over the next 10 to 20 years, will U.S. GBIs and other interceptors improve their ability to destroy ICBM and SLBM warheads and come closer to meeting Nitze’s cost-effectiveness criterion? It is not just about a higher probability of hitting the target; the interceptor should not cost so much that an adversary could cheaply overwhelm the defense by adding warheads and decoys. A major factor affecting the answer to these questions will turn on the ability of radars, other sensors, and the interceptor itself to discriminate between warheads and decoys. GBI tests to date have not involved decoys and other countermeasures that are realistic.8
Another issue is whether there is some level of missile defense capability that the United States would consider adequate to deal with limited rogue-state attacks and, if so, what level that would be. Could that level be sufficiently low that it would not create incentives for Russia and China to increase their strategic offensive forces?
The review should also examine the pluses and minuses of giving SM-3 and THAAD missiles the capability to intercept ICBM- and SLBM-class targets. Creating a second layer to defend the United States may seem attractive. Yet, such capabilities may count for little if the warships carrying the SM-3 interceptors and the ground units equipped with THAAD missiles are deployed forward and thus not positioned to defend the U.S. homeland. Even so, these systems could still incentivize Russia and China to increase their ballistic missile numbers out of concern that the interceptors could be redeployed if needed to defend the homeland.
Missile Defense and Arms Control
Following up on the summit between Biden and Russian President Vladimir Putin in June, U.S. and Russian officials began a strategic stability dialogue. Senior U.S. officials have said they want to reduce reliance on nuclear arms and engage Russia in a negotiation to cover all U.S. and Russian nuclear warheads, not just the deployed strategic warheads constrained by New START. Russian officials, however, have different priorities, including missile defense and long-range conventional-strike weapons.9 Reconciling these competing priorities could pose a major challenge.
The Trump administration’s review stated repeatedly that it would not agree to any limits on missile defenses that are intended to protect against rogue-state ballistic missiles. The Obama administration resisted Russian efforts to bring missile defense into the New START negotiations. The treaty preamble notes the “interrelationship between strategic offensive arms and strategic defensive arms,” but contains just one limit related to missile defense: a prohibition on converting ICBM or SLBM launchers so that they could launch missile interceptors.
One option for Washington is to continue to reject any constraints on missile defense. Unlike its Russian and Chinese counterparts, the U.S. military seems relatively unconcerned about the ability of adversary missile defenses to prevent U.S. ICBMs and SLBMs from reaching their targets. Notably, the Pentagon has not sought limits to constrain Russian missile defenses.
Russian officials, however, could continue to insist on addressing missile defense. In that case, the Biden administration would have to decide whether the U.S. interest in a negotiation covering all U.S. and Russian nuclear weapons is such that it justifies agreeing to confidence- and transparency-building measures on missile defense or even actual limits.
Washington has offered transparency measures in the past. In 2013 the Obama administration proposed an agreement mandating annual data exchanges with current numbers of certain missile defense systems, such as interceptors and radars, and projected numbers each year for the next 10 years. The Russians did not take up the idea.10 Other proposals have included exchanging notifications on missile launches through a Joint Data Exchange Center, an idea that was agreed by the United States and Russia in 1998 but never implemented. The idea was revived in 2011 in discussions regarding a NATO-Russian data fusion center, but the sides reached no agreement.
Washington might also consider actual limits. One idea would be to offer a time-limited ban on the testing or deployment of space-based interceptors. Such systems could pose stability concerns, but neither the U.S. military nor the Russian military has them at present.11 This could offer a way to defuse Moscow’s worst-case fears about U.S. plans.
Another approach would entail numerical constraints on missile defenses. Assuming that a successor to New START would have a duration of 10 to 15 years, with a provision for extension, Washington and Moscow might reach an agreement of similar duration on missile defenses. It appears possible to have a limit that would accommodate the U.S. desire for a capability to defend against limited rogue-state ballistic missile attacks while offering Russia and perhaps China assurance that their strategic ballistic missiles would not require a build-up.
For example, a limit of 100 to 125 strategic interceptors, along with transparency and verification measures, would permit the U.S. military to boost the number of GBIs beyond the 64 it plans to have in 2030. That would provide significant capability against North Korea, but should leave peer competitors with confidence that they could still hold at risk a large number of targets in the United States. Trying to include SM-3, THAAD, S-400, and S-500 missiles would significantly complicate this arrangement.
For the administration, negotiating such GBI limits would prove controversial politically, given the support among Republicans in Congress for strategic missile defense. It might also turn out to be only one of several issues the Russians try to link to a U.S.-desired limit on all U.S. and Russian nuclear weapons.
It appears, however, that a limit could be possible that would allow the U.S. military to maintain a capability to defend against a rogue-state ballistic missile attack while assuring Russia and China that their nuclear deterrents would not be rendered ineffective. That could enable further U.S.-Russian nuclear reductions, lower the likelihood of U.S.-Russian and U.S.-Chinese arms races, and perhaps open the door to a productive strategic stability discussion with Beijing. Hopefully, the Missile Defense Review will offer Biden such options.
1. Greg Thielmann, “The National Missile Defense Act of 1999,” Arms Control Today, July/August 2009, https://www.armscontrol.org/act/2009-07/national-missile-defense-act-1999.
2. Kingston Reif, “Trump Seeks Missile Defense Buildup,” Arms Control Today, March 2019, pp. 30–32, https://www.armscontrol.org/act/2019-03/news/trump-seeks-missile-defense-buildup.
3. Office of the U.S. Secretary of Defense, “2019 Missile Defense Review,” n.d., https://www.defense.gov/Portals/1/Interactive/2018/11-2019-Missile-Defense-Review/The%202019%20MDR_Executive%20Summary.pdf.
4. Cameron Tracy, “De-Hyping China’s Missile Test,” Union of Concerned Scientists, October 21, 2021, https://allthingsnuclear.org/guest-commentary/de-hyping-chinas-missile-test/.
5. “A Conversation With Vice Chairman of the Joint Chiefs of Staff General John E. Hyten,” The Brookings Institution, September 13, 2021, https://www.brookings.edu/wp-content/uploads/2021/09/fp_20210913_hyten_jcs_transcript.pdf.
7. Andrey Baklitskiy, James Cameron, and Steven Pifer, “Missile Defense and the Offense-Defense Relationship,” Deep Cuts Commission Working Paper, No. 14 (October 2021), pp. 23-24, https://deepcuts.org/images/PDF/DeepCuts_WP14.pdf.
8. David Wright, “Decoys Used in Missile Defense Intercept Tests, 1999–2018,” Union of Concerned Scientists, January 2019, https://www.ucsusa.org/sites/default/files/attach/2019/01/Missile-Defense-Intercept-Test-Decoys-white-paper.pdf.
9. Amy F. Woolf, “Nuclear Arms Control After the Biden-Putin Summit,” CRS Insight, IN11694, September 30, 2021, https://crsreports.congress.gov/product/pdf/IN/IN11694.
10. Steven Pifer, “Nuclear Arms Control Choices for the Next Administration,”
Brookings Arms Control and Non-Proliferation Series Paper, No. 13 (October 2016), p. 15, https://www.brookings.edu/wp-content/uploads/2016/10/acnpi_20161025_arms_control_choices_final.pdf.
11. James Timbie, “A Way Forward,” Daedalus, Vol. 149, No. 2 (Spring 2020): 190–204, https://doi.org/10.1162/DAED_a_01797.
Steven Pifer is a William Perry Fellow at the Center for International Security and Cooperation at Stanford University. This article is based on the Deep Cuts Commission working paper “Missile Defense and the Offense-Defense Relationship” co-authored with Andrey Baklitskiy and James Cameron.