A Trident II (D5) missile test, March 26, 2008 Photo Credit: MC1 (SW/AW/SCW) Ronald Gutridge, USSTRATCOM
These views do not represent those of the Department of the Navy, the Department of Defense, or the federal government. They are the personal opinions of the author.
During the Cold War, the U.S. decided to distribute its strategic nuclear forces in a triad comprised of bombers, submarine-launched ballistic missiles (SLBMs), and land-based inter-continental ballistic missiles (ICBMs) because of tactical and technological limitations at the time. Today, however, the triad is outdated. The U.S. no longer needs an ICBM force because its air and sea-based delivery platforms are sufficient for deterrence. Although current modernization plans include maintaining a triad model, the U.S. should retire the ICBM force in favor of a dyad model for three reasons. First, ICBM modernization is expensive, and eliminating ICBMs will allow the government to prioritize funding other key objectives. Second, removing the ICBM force might position the U.S. to include China in arms control agreements. Third, getting rid of ICBMs will underscore Washington’s commitment to Article VI of the Non-proliferation Treaty (NPT), which calls for states to cease arms racing and pursue nuclear disarmament. Overall, US policymakers should seriously consider shifting the US nuclear force structure from a triad to a dyad―comprised of bombers and SLBMs―as a cost-effective way to maintain deterrence and stability.
How We Got the Triad
The US nuclear force structure has evolved over several decades; at first, bombers delivered the atomic bombs in 1945, the U.S. then deployed its first ICBM—Atlas—in 1959, and the Navy began exploring a sea-launched nuclear weapon in 1957, ultimately deploying the ballistic missile submarine (SSBN) USS George Washington in 1961. Washington’s decision to diversify its strategic nuclear delivery systems was rooted in two factors: maximizing survivability and addressing technological limitations.
First, the US triad was primarily created to maximize “Nuclear Weapon system survivability.”[i]According to the Department of Defense (DoD), survivability is “the ability of personnel, equipment, and systems to survive the effects of nuclear weapons.”[ii] After recognizing that US bombers were vulnerable to air defense systems, as demonstrated during the Vietnam War when the North Vietnamese successfully shot down 19 B-52 bombers, the U.S. pursued nuclear-armed ballistic missiles.[iii] Additionally, after concerns were raised over US ICBM survivability during the Cold War because of the threat posed by Soviet ICBMs,[iv] the U.S. began to consider a sea-based strategic nuclear weapon.[v]
Second, early technological limitations inhibited the U.S.’s development of survivable nuclear forces. The U.S. did not develop its first land-based rockets until after World War II. Without the ability to launch a rocket—much less one that could carry a large payload—the U.S. had to rely on bombers to deliver nuclear weapons. Even after the U.S. successfully tested Atlas in 1959, it did not immediately build an SSBN, and three technological limitations explain this delay. First, early ballistic missiles required liquid fuel, which is more volatile than solid fuel. As such, the Navy could not safely place a liquid fuel missile aboard a submarine.[vi] Second, Atlashad to be pressurized while on alert to prevent structural collapse;[vii] maintaining perfect pressure is nearly impossible aboard a submarine. Third, submarines could not accommodate Atlasbecause it was too large,measuring over 26 meters in height; meanwhile, the Nautilus—the U.S.’s primary submarine at the time—had a draft of 8.8 meters. Eventually, the U.S. overcame these technological limitations by deploying Polaris—a stout, solid fuel ballistic missile. Polaris was the Navy’s first submarine-launched ballistic missile (SLBM) deployed aboard USS George Washington in 1961.
Once the triad was created, each leg revealed unique advantages and disadvantages. For example, decisionmakers could recall bombers, unlike ICBMs and SLBMs, in the event of a false launch order or to allow time to negotiate out of a nuclear crisis. Nuclear-armed bombers also allowed leaders to signal an intent to escalate. On the other hand, the U.S. could deploy more ICBMs than the other legs because fewer people were required to operate each missile and, at the time, ICBMs were also more accurate and had greater range than the air and sea-based legs. Furthermore, during the Cold War, missile defense systems against ballistic missiles were considered unfeasible.[viii] Because the submarines were considered virtually impossible to find, they were more survivable than the air and land-based legs of the triad. Submarines’ stealth capabilities also allowed them to deploy SLBMs well within range of their targets without detection. However, the original SLBMs were only effective as countervalue weapons because Polaris, the first SLBM, was less accurate than the ICBM.[ix] Otherwise, as the CNO’s memo noted in 1957, “Submarines are uniquely free from all the disadvantages noted in other weapons systems.”[x]
Status of the Triad Today
Today, the nuclear triad requires modernization. In 2019, General Dunford, the 19th Chairman of the Joint Chiefs of Staff, described triad modernization as “necessary, prudent, and affordable given the nature and evolution of the threats we face.”[xi] Modernization is not necessary for maintaining US nuclear primacy given that the U.S. still has a qualitative advantage in delivery systems; rather, modernization is critical because the equipment in the triad has been extended several decades beyond its original life expectancy, and equipment sustainment will eventually be insufficient.[xii] For example, the Ohio-class SSBNs’ original hull life was 30-years, and it was extended to 42-years.[xiii] What happens when the hull of a submarine fails at depth? It crushes. The rest of the triad is in a similar state.
As such, the Air Force intends to sustain and modernize its current bombers while developing the next-generation bomber called the B-21 Raider. Developers have designed the B-21 with in-air refueling along with stealth capabilities, rendering the B-21’s range nearly endless.[xiv] Moreover, after failing to modernize the Minuteman III ICBMs, the Air Force announced in 2014 that it was developing a new ICBM program called the Ground-Based Strategic Deterrent (GBSD), which will enter service by 2029 and completely replace Minuteman by 2036.[xv] The GBSD will reportedly have improved performance against missile defenses and increased accuracy and range.[xvi] Additionally, the Navy plans to replace the 14 Ohio-class submarines with 12 Columbia-class submarines, starting in 2031, which will give the Columbia-class an operational advantage for decades.[xvii]
Shifting to a Dyad
As the U.S. begins to prioritize modernization, questions have arisen on whether the triad is the best option to continue pursuing. For example, a report from the University of Maryland’s School of Public Policy found that most Americans support phasing out the ICBM.[xviii] Similarly, the 2020 Democratic Party Platform stated the need to balance a strong deterrent with its exorbitant costs.[xix] The questions ask: Do ICBMs add significant deterrence value? When the U.S. deploys at least 10 SSBNs—each with over a hundred warheads—the answer is probably not. Despite such concerns, attempts to eliminate ICBMs have been unsuccessful because supporters of the triad argue that the three legs ensure survivability, complicate adversaries’ war planning, and require the U.S. to change the force posture. For instance, President Obama’s 2010 Nuclear Posture Review (NPR) argued that the triad maintains strategic stability while “hedging against potential technical problems or vulnerabilities.”[xx] President Trump’s 2018 NPR similarly argued that “Eliminating any leg of the triad would greatly ease adversary attack planning and allow an adversary to concentrate resources and attention on defeating the remaining two legs.”
However, these claims are questionable. First, ICBMs are likely already vulnerable. Though ICBM silos are hardened, theoretically making them resistant to a counterforce first strike, hardened targets can be destroyed. For example, in 1985, the US PeacekeeperICBM was created to effectively destroy hardened targets.[xxi] It would be reckless to assume today’s adversaries do not also have this capability—35 years after it was acquired by the U.S. Additionally, when the U.S. first began to harden silos, the Defense Nuclear Agency found that success rates were “not definitive,” as the super-hardened silos were hardly invulnerable to Soviet attack.[xxii]
Eliminating ICBMs is unlikely to make adversaries’ war planning easier because ICBMs do not significantly complicate planning. While Russia has a counterforce nuclear posture and phasing out the ICBM would impact Russia’s attack planning, it does not make their attack planning any easier. A counterforce posture against stationary ICBMs is relatively easy because they do not move; a counterforce posture against bombers and submarines—both mobile and potentially difficult to find—is more complicated. Because ICBMs are also potentially easier for an adversary to defend against compared to SLBMs (because adversaries can see when an ICBM is preparing to launch while SSBNs stay submerged when launching SLBMs), SLBMs provide less warning than ICBM launches, calling into question the effectiveness and utility of ICBMs today.
China’s no-first-use policy and its small nuclear arsenal indicate that Beijing does not have a counterforce posture; therefore, it would likely be unaffected by the U.S. eliminating ICBMs. Furthermore, supporters of the triad argue that ICBMs are essential for maintaining the U.S.’s counterforce nuclear posture. Proponents of the triad suggest that a counterforce posture against countries with large arsenals—like Russia—requires the U.S. to have an ICBM force. However, this is not quantitively accurate because it ignores the payload of a single Ohio-class SSBN. Russia has approximately 300 ICBM launchers. Assuming eliminating a silo requires about two warheads, the US would need 600 warheads. Seven Columbia-class SSBNs would carry more than enough warheads to conduct such a strike. Purchasing several more SSBNs would also be cheaper over 30 years than the GBSD program.[xxiii]
Therefore, eliminating the ICBM-leg of the triad would yield several advantages. First, this measure would save the US government money. The Congressional Budget Office projects ICBM modernization to cost $149 billion over the next 30 years. Although this is a relatively low price tag compared to the other legs, these funds would be better spent offsetting the Columbia-class’s burden on the Navy’s shipbuilding budget. Alternatively, the money could go unspent and, instead, help reduce overall defense spending. Second, creating a dyad could reduce deployed warheads and incentivize China to participate in arms control negotiations. China has refrained from entering strategic arms control negotiations because US nuclear levels are significantly higher than China’s.[xxiv] Even though US nuclear forces would vastly outnumber China’s if Washington cut 400 deployed warheads, a recent DoD report predicted that China’s warhead count will “at least double in size” in the next decade.[xxv] Together, these two developments might bring US and Chinese nuclear forces within a quantitative range where an arms control agreement is feasible—even if the U.S. maintains a quantitative and qualitative advantage. Third, reducing the U.S.’s reliance on nuclear weapons, as signaled by eliminating the ICBM force, would demonstrate compliance with Article VI of the NPT. Allies praised previous arms control agreements as a step in the right direction, and a unilateral step towards disarmament could reassure other countries that the U.S. values denuclearization but still prioritizes the security of itself and its allies.
A Critical Juncture
In a September 2020 testimony before the Senate Armed Services Committee, Undersecretary of Defense for Acquisition and Sustainment Ellen Lord described the nuclear enterprise as reaching a critical juncture that could cause catastrophe if necessary actions are not taken. She is correct. We have reached a unique point where the U.S. can effectively transition to a strategic nuclear dyad and still preserve the survivability of our nuclear forces while strengthening the capabilities of our air and sea-based legs. Crucially, this will save US taxpayers billions of dollars over the medium to long-term, which could be better spent on various efforts related to other national security or domestic issues. The conditions that contributed to the creation of the triad no longer apply, given that SLBMs are accurate, and US SSBNs can ensure massive retaliation. At a time when the U.S. faces an impending recession and a deteriorating arms control regime, signaling nuclear restraint could go a long way in helping our country foster global stability and security.
 The Office of the Deputy Assistant Secretary of Defense for Nuclear Matters (ODASD(NM)), Nuclear Matters Handbook 2020, 141. https://www.acq.osd.mil/ncbdp/nm/nmhb/
 The Office of the Deputy Assistant Secretary of Defense for Nuclear Matters (ODASD(NM)), Nuclear Matters Handbook 2020, 141.https://www.acq.osd.mil/ncbdp/nm/nmhb/
 “The American ICBM Program,” The National Park Service, October 20, 2020, https://www.nps.gov/articles/mimiarmsrace-03.htm
 Bruce Bennett, “How to Assess the survivability of the U.S. ICBMs,” Rand, June 1980, iii. https://www.rand.org/content/dam/rand/pubs/reports/2006/R2577.pdf
 Chief of Naval Operations, “Study on the Introduction of the Fleet Ballistic Missile into Service, January 20, 1957, 1. https://assets.documentcloud.org/documents/6895252/National-Security-Archive-Doc-04-U-S-Navy-Naval.pdf.
 Wyndham Miles, “the Polaris,” Technology and Culture, Autumn, 1963, Vol. 4, No, 4, 480.
 “The Atlas Missile,” The National Park Service, October 20, 2020, https://www.nps.gov/articles/atlas-icbm.htm
 Stephen Walt, “The Rush to Failure,” Harvard Magazine, May 1, 2000, https://harvardmagazine.com/2000/05/rush-to-failure-html (accessed November 11, 2020).
 Ibid., 7.
 Chief of Naval Operations, “Introduction of the Fleet Ballistic Missile,” 8.
 Joseph Dunford, “Statement to Senate Armed Services Committee regarding Department of Defense Budget Hearing,” March 14, 2019, 8.
 Department of Defense, 2018 Nuclear Posture Review, February 2018,ii.
 Ronald O’Rourke, “CRS Report: R41129-Navy Columbia (SSBN-826) Class Ballistic Missile Submarine Program: Background and Issues for Congress,” Congressional Research Service, October 7, 2020, 2. https://fas.org/sgp/crs/weapons/R41129.pdf
 Alex Hollings, “The Most Advanced Bomber Ever: Here’s What we Know About the B-21 Raider,” Sandboxx, August 23, 2020, https://www.sandboxx.us/blog/the-most-advanced-bomber-ever-heres-what-we-know-about-the-b-21-raider/#:~:text=Although%20it’s%20expected%20the%20the,long%20enough%20to%20support%20it
 Amy Woolf, “CRS Report: RL33640-U.S. Strategic Nuclear Forces: Background, Developments, and Issues,” April 27, 2020, 43. https://fas.org/sgp/crs/nuke/RL33640.pdf
 Amy Woolf, “CRS Report: RL33640,” 18-20; “Department of the Air Force awards contract for new ICBM system that enhances, strengthens US triad, Secretary of the Air Force Public Affairs, September 8, 2020, https://www.af.mil/News/Article-Display/Article/2340139/department-of-the-air-force-awards-contract-for-new-icbm-system-that-enhances-s/
 Owen Cote, “Invisible nuclear-armed submarines or transparent oceans? Are ballistic missile submarines still the best deterrent for the United States?” Bulletin of the Atomic Scientists, vol. 75, no. 1: 30-5.
 University of Maryland, School of Public Policy, “The Common Ground of the American People: Policy Positions Supported by Both Democrats and Republicans,” 20. https://vop.org/wp-content/uploads/2020/08/Common_Ground_Brochure.pdf
 “2020 Democratic Party Platform,” Democratic Convention Convention, 81. https://www.demconvention.com/wp-content/uploads/2020/08/2020-07-31-Democratic-Party-Platform-For-Distribution.pdf
 Department of Defense, 2010 Nuclear Posture Review Report, April 2010, 21. https://dod.defense.gov/Portals/1/features/defenseReviews/NPR/2010_Nuclear_Posture_Review_Report.pdf
 “Status of the Intercontinental Ballistic Missile Modernization Program,” Government Accountability Office, July 8, 1985, 13; 34. https://www.gao.gov/assets/150/142998.pdf
 Walter Pincus, “New Silo Hardening test Could Reopen Missile Basing Debate,” The Washington Post, May 11, 1984, https://www.washingtonpost.com/archive/politics/1984/05/11/new-silo-hardening-tests-could-reopen-missile-basing-debate/861520be-89e7-4508-b35c-8d96d87ce02a/
 The Columbia-class will cost a total of $314 billion for 12 boats over 30 years. This amounts to about $26.5 billion per boat.
“Projected Costs of the U.S. Nuclear Forces, 2017 to 2026,” Congressional Budget Office, February 14, 2017, https://www.cbo.gov/publication/52401
 “China ‘happy to’ join arms control talks with US and Russia—if US cuts its nuclear arsenal down to China’s level,” Business Insider, July 8, 2020, https://www.businessinsider.com/china-join-new-start-talks-if-us-cuts-nuclear-arsenal-2020-7  Department of Defense, “Report to Congress: Military and Security Developments Involving the People’s Republic of China, 2020,”, ix. https://media.defense.gov/2020/Sep/01/2002488689/-1/-1/1/2020-DOD-CHINA-MILITARY-POWER-REPORT-FINAL.PDF