Finally, the United States relies on nuclear deterrence to check Chinese and Russian nuclear attacks upon the homeland because it has no choice. U.S. homeland missile defenses cannot prevent Russian and Chinese nuclear forces from inflicting damage upon the United States. With respect to North Korea, the United States does have a choice: it can accept vulnerability to North Korean ICBMs and rely on deterrence, or it can modernize and expand its missile-defense capabilities to stay ahead of the threat. It is a matter of priorities, not cost or technical feasibility. 

How will Russia and China respond? Will it lead to a breakdown in arms control and a new nuclear arms race?

Despite U.S. government assurances that homeland defenses are meant only for the rogue state threat, Russia and China likely will interpret expanding defenses as a threat to their nuclear retaliatory capability, potentially driving an arms race. While Russia and China bemoan improvements to U.S. homeland defenses, each continues to modernize their own suite of missile defense systems while at the same time expanding nuclear arsenals.

For the foreseeable future, Chinese and Russian offensive nuclear forces would easily outnumber the proposed underlayer. The 2010 New START Treaty permits Russia to field 1,550 warheads on 700 delivery vehicles. China’s intercontinental nuclear capability currently consists of about 104 ICBMs (some with multiple warheads) and seventy-two submarine-launched ballistic missiles, and China publicly revealed a new nuclear-capable heavy bomber with the ability to carry air-launched ballistic missiles.

Russia and China have developed a range of technologies (including various types of decoys, chaff, and jamming, among others) to counter U.S. missile defense systems. At the same time, China’s ongoing expansion of its ICBM fields and the expansion of its submarine ballistic missile force—which the intelligence community believes will reach parity with the U.S. arsenal by the 2030s—underscores the point that such an underlayer will not impact China and Russia’s ability to hold the American homeland at risk.

Given the limited number of SM-3 and THAAD missiles, as well as the interceptors’ technological limitations against Russian and Chinese missiles, these capabilities will not upset strategic stability for the foreseeable future, if ever. As President Vladimir Putin noted, by the end of 2023, 90 percent of Russia’s nuclear forces will be modernized and, in his words, “capable of confidently overcoming existing and even projected missile-defense systems.”

Historical experience shows that missile defense and nuclear arms control are not incompatible. For example, even though the United States has been pursuing missile defenses seriously since the mid-1980s, Russia and the United States have together drawn down their nuclear forces by some 85 percent from Cold War highs. If Russian leaders were seriously alarmed about U.S. missile defenses, they would not have agreed to these reductions.

Some have suggested that Russia’s “novel” nuclear systems (e.g., nuclear-powered cruise missiles, long-range nuclear undersea torpedo, and hypersonic glide warheads) are a response to U.S. missile-defense plans. But according to Rose Gottemoeller, former New START chief negotiator, Putin “is after nuclear weapons for another reason—to show that Russia is still a great power to be reckoned with. These exotic systems have more of a political function than a strategic or security one.”

Recommendations

It would clearly be wise to strengthen our limited missile defenses in the homeland by exploring the utility and feasibility of an underlayer. Specifically:

The MDA should conduct an additional SM-3 test against an ICBM target. Such a test would give greater confidence in the utility of SM-3 defenses against ICBM threats and is a requisite first step to better understanding the viability of an underlayer. 

The MDA should explore the utility of Aegis ashore and THAAD against North Korean ICBM threats. A full exploration of the utility of the underlayer, including deep technical analysis, is required if the United States wants to strengthen its defenses. In particular, the technical feasibility of these systems’ ability to successfully engage ICBMs is required. This is the first step in exploring an underlayer.

The Department of Defense should explore the requisite operations concepts and plans for an underlayer. NORTHCOM, in conjunction with the U.S. Navy, should ensure that plans and procedures are in place to employ existing Aegis BMD ships armed with the SM-3 IIA missile in an emergency, should North Korean ICBMs threaten the United States during a crisis or conflict. Increasing production of the SM-3 IIA missile would augment this capability over the next few years.

The department should also identify costs associated with fielding a limited number of Aegis ashore and THAAD batteries in critical locations within the homeland. In a fiscally constrained environment, cost must be addressed. Identifying required costs associated with a prioritized underlayer against key targets is a necessary step to an ultimate decision on whether to field an underlayer.

Conclusion

In the final analysis, any administration must weigh the strategic benefits of defending the homeland against rogue missile threats alongside the potential consequences for our relationship with Russia and China. U.S. missile defense, including the underlayer, is a crucial enabler of U.S. national security strategy, and the potential downsides with Russia and China are overstated.

Defense of the American people against rogue nation nuclear threats should be an obvious priority for policymakers. Less appreciated is that the perception of such protection is essential for a U.S. strategy that ultimately relies on the support of allies. Allies, in turn, count on the United States to run risks on their behalf. If the United States is unwilling to take the steps necessary to defend itself against a country such as North Korea, allies could conclude that Washington may think twice before coming to their assistance in time of need. Missile defense improves America’s freedom of action to protect its allies and global interests.

Russian and Chinese own investments in missile defense belie their criticism of American missile defense systems. Whatever concerns they may hold about our future capabilities, U.S. missile defense plans have not stood in the way of drastic nuclear arms control reductions between Russia and the United States.

Policymakers simply cannot give Russia or China a veto over the protection of the United States against rogue state threats. Far from upsetting strategic stability with Russia and China, improved and expanded homeland defenses, including a potential underlayer, will contribute to collective alliance efforts to meet the challenges posed by rogue actors armed with ICBMs.

Robert Soofer is a senior fellow in the Atlantic Council’s Scowcroft Center for Strategy and Security. He served as deputy assistant secretary of defense for nuclear and missile defense policy from April 2017 to January 2021.

Image Credit: Creative Commons.