In my introduction to the fourth monograph in this 

ACIS Papers series, I focused upon the innovations the U.S. 

Government has brought to nuclear weapons policy and 

deterrence during the last four years as part of a broader –

and long overdue – U.S. return to great power competitive 

strategy in response to threats presented by the People’s 

Republic of China (PRC) and the Russian Federation. These 

innovations include the honesty and clarity we brought to 

U.S. declaratory policy in the 2018 Nuclear Posture Review

(NPR), the conceptual and diplomatic outreach of our new 

“Creating an Environment for Nuclear Disarmament” 

initiative, and our call for trilateral arms control to avert a 

nuclear arms race with Moscow and Beijing.

The main focus of ACIS Paper #4 however, was upon 

fielding of the low-yield U.S. submarine-launched nuclear 

warhead, the W76-2, which entered into service earlier this 

year. The main body of that monograph walked through 

the U.S. thinking and policy behind the development and 

deployment of this warhead, and the ways in which it will 

contribute to deterrence and the reduction of nuclear risks 

in light of the threat of limited nuclear attacks against the 

United States and its allies. 

Except in passing, however, ACIS Paper #4 did not 

mention ongoing U.S. work to reintroduce a nuclear-armed 

sea-launched cruise missile (SLCM-N) capability to the U.S. 

arsenal. We at the State Department are therefore 

grateful to our colleagues in the Office of the Under 

Secretary for Policy at the Department of Defense (DOD) 

for stepping up to offer just such an explication. The 

attached DOD paper discusses SLCM-N in detail, and 

represents an important step forward as we in Washington

– in sharp contrast to our counterparts in Moscow and 

Beijing – model transparency and public accountability in 

nuclear weapons policy and doctrine. 

Before we turn to the DOD paper itself, however, it 

may be useful to remind readers of the context out of 

which the SLCM-N question arose, for the security 

environment facing U.S. nuclear planners today looks 

depressingly unlike what it was assumed this country would 

face at the time of the previous Nuclear Posture Review in 

2010. It is important to recall that SLCM-N is not a new 

type of capability for the United States. Indeed, we had a 

sea-launched cruise missile with a nuclear warhead 

deployed at sea for a decade until it was stored ashore in 

accordance with the U.S. 1991 Presidential Nuclear 

Initiatives and then ultimately retired by the Obama 

Administration. The SLCM-N initiative simply represents a 

decision to restore a nuclear-tipped SLCM capability to 

maintain deterrence in the face of a sharp deterioration in 
the global security environment that has again created a 

need for one. 

Our previous nuclear-armed SLCM was the Tomahawk 

Land Attack Missile-Nuclear (TLAM-N) – a nuclear-tipped 

variant of the U.S. Navy’s venerable Tomahawk cruise 

missile, variations of which have been in service since the 

early 1980s. TLAM-N survived the Clinton Administration’s 

1994 decision to eliminate the nuclear capability for the 

Navy’s surface ships, thereafter remaining available for 

service on U.S. nuclear-powered submarines, but the 

Obama Administration decided to eliminate it, announcing 

that decision in 2010.

As explained in the 2010 Nuclear Posture Review, this 

decision was based largely on the overall conclusion that 

the strategic environment had changed in ways that made 

a nuclear-tipped SLCM unnecessary. According to the 2010 

NPR, it was appropriate to eliminate the capability 

represented by TLAM-N because the deterrence challenge 

facing the United States was now “fundamentally 

different” than it had been before, as the risk of major 

power confrontation had dimimished. Indeed, the biggest 

challenge facing the country then was said not to be that of 

deterring aggression by a major power such as Russia or 

China, but rather “preventing nuclear proliferation and 

nuclear terrorism” – struggles in which nuclear-armed 

cruise missiles were of little help. 

The 2010 NPR stressed, for instance, that “the nature 

of the U.S.-Russia relationship has changed fundamentally 

since the days of the Cold War,” with the result that 

Washington and Moscow 

“are no longer adversaries, and prospects for military 

confrontation have declined dramatically. The two 

have increased their cooperation in areas of shared 

interest, including preventing nuclear terrorism and 

nuclear proliferation.”

As for the PRC, 2010 NPR did express concerns about 

its lack of transparency and “the pace and scope of China’s 

current military modernization efforts, including its 

quantitative and qualitative modernization of its nuclear 

capabilties.” It also raised “questions about China’s future 

intentions” in the nuclear arena. Nevertheless, the Obama 

Administration’s approach was fundamentally optimistic, 

emphasizing that “[t]he United States and China are 

increasingly interdependent” and have “shared 

responsibilities for addressing global security threats.” 

This assessment of the overall security context –

namely, that “changes in the nuclear threat environment” 

had made it less challenging and that there was “less 

dangerous strategic interaction” between the United 

States, Russia, and the PRC – was a critical ingredient of 

Obama Administration policy. For present purposes, 

however, it is notable as the conceptual foundation upon 

which that Administration made its decision to eliminate 

the existing nuclear SLCM. 

Indeed, in President Obama’s signature “Prague 

Speech” in April 2009, he situated his Administration’s 

efforts to cut back U.S. nuclear weapons capabilities in a 

broader effort to catalyze further change in the 

international arena: 

“To put an end to Cold War thinking, we will reduce the 

role of nuclear weapons in our national security 

strategy, and urge others to do the same.”

Where we led, he reasoned, others would follow – but this 

progress had to begin with the United States: “we will begin 

the work of reducing our arsenal.” 

Eliminating TLAM-N was, accordingly, a part of this 

move. By 2013, U.S. Navy documents had stopped 

referring to the missile and the entire stockpile of TLAMN’s W80-0 warheads had been dismantled.

The present-day reader, of course, can see the 

fundamental problem with those 2010 assumptions, for 

things unfortunately turned out rather differently. Looking 

back at them a decade later, in fact, those conclusions

about a less threatening and steadily-improving global 

security environment sound almost quaint – or even naive.

After all, by the time of the 2010 NPR, Russia had in 

2008 invaded one of its neighbors – the sovereign state of 

Georgia – and carved out parts of that country into puppetrun proxy pseudo-states that remain occupied by Russian 

forces to this day. As we later learned, Russia at that time

was likely already a couple of years into covertly testing its 

new SSC-8 missile – a system that the Obama 

Administration declared a violation of the Intermediaterange Nuclear Forces (INF) Treaty in 2014, and that would 

ultimately destroy that reaty. In retrospect, it is also likely

that Russia was by then well into the process of developing 

some or all of the exotic new strategic nuclear systems 
about which President Vladimir Putin would later boast in 

his March 2018 State of the Union address. 

Russia was even then also already well understood to 

be a chronic violator of the Open Skies Treaty, having

imposed illegal airspace restrictions on treaty overflights 

on a more or less continuous basis from 2004 through 

2008. It is also now clear that Russia had not adhered to all 

of the commitments it made as part of the Presidential 

Nuclear Initiatives (PNIs) of the early 1990s concerning 

elimination of many of its non-strategic nuclear forces. It 

may even be that Russia had by 2010 “conducted nuclear 

weapons experiments that have created nuclear yield and are 

not consistent with the U.S. ‘zero-yield’ standard.” 

And things since then have only gotten worse. Today, 

in 2020 – the strategic and geopolitical challenges 

presented by Russia look even more stark. In broadest 

terms, it is now all too clear that

“Russia seeks to restore its sphere of influence, both in 

the countries of its so-called ‘near-abroad’ (e.g., 

Ukraine and Georgia) and by acquiring client states 

farther afield (e.g., Syria) through the use of blatant 

military aggression, proxy forces, political and military 

subversion, and the manipulation of political, 

economic, energy, and military relationships. It is also 

essential to Russia’s strategy to weaken U.S. alliance 

relationships with Europe and elsewhere, as well as 

undermining and discrediting U.S. global leadership.

“Russia’s tactics in pursuit of these objectives tend to 

be destructive rather than constructive ... [and it is] 

notably risk-tolerant in its policy choices, not shying 

away from reckless gambles and extravagant 

provocations (e.g., its invasions of Georgia and 

Ukraine, overseas expeditionary warfare in Syria, the 

deployment of ‘private’ military contractors to 

hotspots around the world, interference in Western 

elections, and assassinations or assassination attempts 

against defectors in the West using radioactive poisons

and illegal chemical weapons).”

Nor are Kremlin provocations in the nuclear arena

today in any way diminished. Quite to the contrary. 

Moscow is pushing forward on 

 

“

Worryingly, the Russia problem is also much greater 

than just these new strategic systems. As the U.S. Defense 

Intelligence Agency has summarized,

“[Russia’s] overall nuclear stockpile is likely to grow 

significantly over the next decade. This assessed 

growth is primarily driven by a significant projected 

increase in the number of Russia’s nonstrategic nuclear 

weapons. Russia is adding new military capabilities to 

existing stockpile of nonstrategic nuclear weapons, 

including those employed by ships, aircraft and ground 

forces. These nuclear warheads include theater and 

tactical range systems that Russia relies on to deter 

and to defeat NATO or China in a conflict.

“Russia’s stockpile of nonstrategic nuclear weapons, 

already large and diverse, is being modernized with an 

eye towards greater accuracy, longer ranges and lower 

yields to suit their potential war-fighting role. We 

assess Russia to have dozens of these systems already 

deployed or in development.”

And then there is China. For its part, the PRC’s 

behavior has also notably worsened, and the strategic 

threats it presents have grown. 

“The PRC seeks a military more capable than any other 

in the world by 2049; hegemony in the Asia Pacific 

region (and one that implicitly erodes U.S. presence); 
leading positions within international organizations; 

and a dominant position in the advanced technologies 

essential to military power. With these 

achievements, the PRC hopes to claim what it sees as 

its natural hegemonic place at the center of a system 

that generally defers to Beijing’s interests.

“To these ends, the PRC seeks to expand its so-called 

‘comprehensive national power’ (CNP) through a mix 

of political, economic, military, and ‘soft power’

initiatives. It approaches this effort on a whole-ofsystem basis capable of, and dedicated to, mobilizing 

every aspect of Chinese society via the coercive power 

of the CCP police state.

“The PRC’s effort to expand its CNP includes a 

significant expansion of the capabilities of the People’s 

Liberation Army (PLA), including its nuclear forces, 

with an emphasis upon high-technology tools that can 

help disrupt or completely deny U.S. access to key 

areas of the Indo-Pacific in a crisis.”

Even as Beijing’s revisionist geopolitical ambition has 

grown – or at least been permitted finally to find expression 

as the PRC’s growing power and heft in international 

relations has allowed it more freedom of maneuver – so too 

have its nuclear capabilities been expanding. While the 

PRC still has a smaller nuclear arsenal than either the 

United States or Russia, 

“both qualitatively and quantitatively it is expanding 

this arsenal rapidly ... along the road to what Xi Jinping 

has described as his ‘Strong Military Dream’ in which 

Beijing intends to develop the most advanced military 

capabilities by 2049. The PRC is building a vast new 

range of both strategic and non-strategic delivery 

systems, including new heavy ICBMs, hypersonic 

delivery vehicles, a new ballistic missile submarine, an 

air-launched ballistic missile, and a whole quiver full of 

missiles that can interchangeably carry either nuclear 

or conventional warheads.”

Over the next decade, in fact, China will likely “at least 

double the size of its nuclear stockpile in the course of 

implementing the most rapid expansion and diversification 

of its nuclear arsenal in China’s history.” And the PRC will 

have many ways to deliver such weapons. For instance, in 

2019 it launched more ballistic missiles for testing and 

training than the rest of the world combined.

All in all, the strategic environment that we face today 

is radically unlike the one that the drafters of the 2010 NPR 

seem to have anticipated – and that they hoped actually to 

help produce by leading with U.S. reductions. It is 

impossible to understand the current U.S. approach to 

SLCM-N without appreciating this context. The truth is 

that the assumptions that underlay the Obama 

Administration’s decision to abandon nuclear-armed SLCM 

capabilities have, unfortunately, proven incorrect.

Even beyond specific issues of nuclear force posture, 

moreover, the sweep of these geopolitical changes – and 

the deterioration on the global security environment that 

they have created – also make clear why it was so 

necessary that a return to an emphasis upon great power 

competition be central themes of the 2017 U.S. National 

Security Strategy and 2018 National Defense Strategy. 

The broader U.S. policy shifts now underway are a 

response to a range of provocative and destabilizing 

choices by the PRC and Russia, two “ambitious and 

increasingly self-assertive autocratic regimes [which] conceive 

it to be their mission to upend the global order in the service of 

their own embittered geopolitical identity politics.” 

And so great power competition has unfortunately 

again become the order of the day. As explained in the 

recently-published United States Strategic Approach to the 

People’s Republic of China, for instance, to respond to the 

challenges presented by PRC behavior,

“the Administration has adopted a competitive 

approach to the PRC, based on a clear-eyed 

assessment of the CCP’s intentions and actions, a 

reappraisal of the United States’ many strategic 

advantages and shortfalls, and a tolerance of greater 

bilateral friction.”

Much the same thing can be said of Russia: the 2018 

National Security Strategy describes both Russia and the 

PRC as “revisionist powers ... actively competing against 

the United States and our allies and partners.” 

Accordingly, as noted in the National Defense Strategy, 

U.S. prioritization has also had to evolve with the times. 

Whereas the Obama Administration had, as noted, 

downplayed great-power strategic threats in order to focus 

upon nuclear terrorism and nonproliferation – and had, 

inter alia, eliminated TLAM-N on this basis – developments

in the PRC and Russia have driven the Trump 

Administration once again to the conclusion that “[i]nterstate strategic competition, not terrorism, is now the 

primary concern in U.S. national security.” As the attached 

DOD paper makes clear, our renewed pursuit of a nuclear-
armed SLCM grows out of the duty that every U.S. 

Administration has, as a steward of the safety and security 

of the American people, to preserve deterrence in light of 

prevailing threats. As the security environment has 

deteriorated, the United States must approach its nuclear 

posture differently than it did when it believed the world 

was becoming a steadily safer place.

That said, it should also be remembed what the United 

States is not doing, even in response to these grave 

challenges. Most obviously, we are not significantly 

expanding the size of our nuclear arsenal. The W76-2 did 

not increase the number of deployed U.S. nuclear 

weapons, and we will not seek to match Russia’s theaterrange nuclear arsenal weapon-for-weapon via SLCM-N. 

Indeed, as our current modernization program 

progresses, we will actually reduce the number of deployed 

submarine-launched ballistic missiles with introduction of 

the Columbia-class SSBN.2 This is on top of the 

extraordinary U.S. nuclear reductions that by 2017 had 

already cut the size of our arsenal by something like 87 

percent from its Cold War peak. Additionally, the United 

States is today leading the charge in pursuing a trilateral 

arms control framework with both the PRC and with Russia

in order to avert a dangerous new nuclear arms race, even if 

Beijing still refuses to come to the table. 

Even if others may have forgotten their own 

responsibilities, we remain fully aware of our legal 

 

obligation under Article VI of the Nuclear Nonproliferation 

Treaty to pursue negotiations in good faith on effective 

measures relating to averting a nuclear arms race. As 

noted, in fact, we have repeatedly called upon Moscow and 

Beijing to join us in just such negotiations. 

Yet it is also the case that the United States cannot 

stand by and allow deterrence to erode as a result of 

destabilizing nuclear posture choices being made in the 

Kremlin, and in the Chinese Communist Party’s leadership 

compound in Zhongnanhai. Our approach is thus a 

balanced one. Even as we take whatever steps are needed 

in order ensure that deterrence does not fail, we also seek 

new agreements to forestall destructive arms race behavior 

and to build dialogue in order – as the Preamble to the NPT 

exhorts everyone – to ease international tension and 

strengthen trust between states in order to facilitate 

disarmament. 

The attached DOD paper explains how the various 

prongs of U.S. strategy and policy come together in our 

SLCM-N program, and I commend it to you.

– Dr. Christopher Ford

Assistant Secretary of State

Performing the Duties of the Under Secretary for Arms 

Control and International Security
prepared by the

Office of the Under Secretary of Defense for Policy

U.S. Department of Defense

Executive Summary

A nuclear-armed sea-launched cruise missile (SLCM-N) 

is one of two supplemental capabilities identified in the 

2018 Nuclear Posture Review (NPR) as needed to address 

specific regional deterrence problems that have emerged in 

recent years as a result of developments in the forces and 

doctrine of nuclear competitors.

First, there is a growing disparity between the 

nonstrategic nuclear weapons (NSNW) fielded by the 

United States and the Russian Federation. While in the 

past this imbalance was manageable, changes in Russian 

behavior in recent years, their continued investment in 

these systems, and their refusal to consider an arms control 

alternative has created a more serious risk, requiring the 

United States to take countervailing steps to address this 

disparity.

Second, there are credible concerns that these 

capabilities are central to a Russian approach to regional 

conflict that envisions the early, limited use of nonstrategic 

weapons to end a war on terms favorable to Russia. This 

approach may be premised on Russia’s belief that its 

expanding anti-access/area denial (A2AD) networks will be 

able to neutralize the airborne nuclear deterrent forces of 

the United States and NATO. In the future, it is possible 

that China could adopt a similar doctrine. Developing and 

fielding SLCM-N signals the leaders of nuclear competitors 

in a concrete way that the United States has the capability 

and will to maintain operationally effective nuclear options 

to deter regional aggression. 

Third, the deteriorating global nuclear threat 

environment is a source of concern to regional allies and 

partners, who are looking to the United States to 

strengthen the framework for assurance and extended 

deterrence vital to their own security and non-nuclear 

status. SLCM-N will bolster allied confidence in U.S. 

security guarantees.

Through its unique attributes, SLCM-N is a tailored 

response to these challenges to deterrence stability. It will 

lower the risks of nuclear conflict, bolster the confidence of 

allies, and restore a degree of balance in nonstrategic 

nuclear weapons that could create conditions more 

conducive to addressing this category of forces through 

arms control. This approach does not require nuclear 

testing or new nuclear weapons nor does it violate any 

treaty.
This paper addresses the strategic requirement for and 

deterrence benefits of a nuclear-armed sea-launched cruise 

missile (SLCM-N). The 2018 Nuclear Posture Review (NPR) 

identified this system as a necessary supplement to the 

Triad. The paper focuses on the deterrence rationale for 

SLCM-N, the unique attributes of SLCM-N in the emerging 

operational environment, arms control and stability 

considerations, and frequently heard critiques of SLCM-N. 

The key points put forward in this paper are as follows:

1. The NPR supplemental capabilities are modest and 

sensible adaptations that respond to genuine 

deterrence risks that have arisen in recent years.

2. SLCM-N responds in a unique way to a deteriorating 

nuclear threat environment and a growing imbalance 

in nonstrategic nuclear weapons.

3. SLCM-N will play an important role in tailored 

deterrence strategies in both Europe and Asia.

4. SLCM-N’s operational attributes reinforce its value as a 

regional deterrence capability.

5. SLCM-N is not a redundant capability and does not 

duplicate the mission of other existing or planned 

nuclear systems.

6. Developing SLCM-N is an urgent task and initial steps 

in the acquisition process are underway.

The NPR is part of a larger set of strategic initiatives 

reshaping U.S. national security to strengthen the nation’s 

ability to deter conflict, defend vital interests, and promote 

global security. The National Security Strategy (NSS) and 

the National Defense Strategy (NDS) emphasize new 

challenges to deterrence arising from renewed great power 

competition and the growing capabilities of rogue regimes. 

To respond to these challenges, the United States must 

restore its competitive advantage and develop the 

capabilities needed to deter and defend across an 

increasingly dynamic set of threats. Although nuclear 

forces are but one element of this, they remain 

foundational to U.S. strategy and an effective means to 

deter a number of significant threats to the United States 

and its allies and partners. Accordingly, we will sustain a 

nuclear force that both meets the requirements of credible 

deterrence today and anticipates future risks.

Key among the adaptations identified in the NPR are 

modest enhancements intended to supplement the 

capabilities provided by Triad forces (submarines, 

intercontinental ballistic missiles, and strategic bombers). 

These supplemental capabilities are a response to 

developments in competitor forces and doctrine that 

undermine deterrence stability at the regional level. 

Several challenges stand out: a deteriorating global 

nuclear threat environment, a growing disparity in 

nonstrategic nuclear weapons (NSNW), a more complex 
operating environment for nuclear-capable aircraft, the 

requirements of allied assurance and extended deterrence; 

and the possibility that an adversary will employ a limited 

number of nuclear weapons—including low-yield 

weapons—to deter U.S. military responses to regional 

aggression. To address this range of risk, we have adapted 

one existing capability and we will reconstitute—in updated 

form—a second. We have fielded a small number of 

existing submarine-launched ballistic missile (SLBM) 

warheads with a low-yield capability. In the longer-term, 

we will develop a modern nuclear-armed sea-launched 

cruise missile—a capability previously fielded but retired by 

2012 in hopes of persuading other states to eliminate these 

and related weapon systems.

These programmatic initiatives are not being 

undertaken lightly, but in the belief they are necessary to 

provide greater flexibility in tailoring strategies to deter 

and if necessary respond to limited nuclear threats, and to 

signal to Russia —and to China, which is also developing 

theater-range, dual capable systems — that there is no 

exploitable advantage to be gained from the threat or use 

of nuclear weapons in a regional conflict. Despite 

arguments that are commonly heard, the goal is not to 

mimic Russia’s strategy or match its much more expansive 

nonstrategic arsenal. The NPR supplemental capabilities 

fall well short of doing so. Nor do they signal a shift 

toward a strategy emphasizing nuclear warfighting or a 

lower threshold for nuclear employment. To the contrary, 

they are intended to ensure that nuclear war is less rather 

than more likely by demonstrating to adversaries that the 

United States is fully prepared to deter nuclear threats at 

every stage of an escalating crisis or conflict. This will raise, 

not lower, the “nuclear threshold.” The supplemental 

capabilities are consistent with U.S. obligations under the 

New START Treaty. They will not add to the number of 

nuclear weapons in the U.S. nuclear stockpile, create arms 

race pressures, upset the overall nuclear balance, or 

undermine stability. They will leverage existing missile and 

warhead programs. Deployed at sea, these systems will 

not place added burdens on allies for basing and support.

SLCM-N Directly Addresses the Growing Disparity in 

Nonstrategic Nuclear Weapons 

SLCM-N has particular value as a response to one of 

the more troubling trends in adversary nuclear 

capabilities—the imbalance in NSNW and the continued 

and increasing Russian investment in this category of 

forces. This investment indicates Russian authorities may 

view these capabilities as flexible and usable on the 

battlefield as an adjunct to conventional forces. Russia is 

modernizing an active stockpile of up to 2,000 such 

weapons that it can deploy on naval platforms, aircraft, and 

with ground forces. This includes at least twenty individual 

weapons or weapon systems that encompass ballistic 

missiles, ground-, air- and sea-launched cruise missiles, 

gravity bombs, torpedoes, depth charges, and surface-toair missiles. By contrast, NSNW deployed by the United 

States in Europe in support of NATO remain modest in 

number and limited to one type of weapon. This capability 

is being modernized but not expanded in size. 

The asymmetry in NSNW in Europe has long been a 

source of concern precisely because of the fear that it could 

contribute to deterrence instability in a crisis. This danger 

was highlighted a decade ago by the Strategic Posture 

Commission led by former secretaries of defense William 

Perry and James Schlesinger, by the United States Senate 

in the New START Resolution of Ratification, and by the 

2010 NPR.

Strategic Posture Commission: “The imbalance in

NSNW is of rising concern and an illustration of the new 

challenges of strategic stability as reductions in strategic 

weapons proceed.”

New START Resolution of Ratification: “The US will seek 

to initiate...not later than one year after entry into force 

of the New START Treaty, negotiations with the Russian 

Federation...to address the disparity between the nonstrategic (tactical) nuclear weapons stockpiles of the 

Russian Federation and of the U.S.”

2010 NPR: “...large disparities in nuclear capabilities 

could raise concerns on both sides and among US allies 

and partners, and may not be conducive to maintaining 

a stable, long-term strategic relationship.”

For this reason the United States has consistently 

called on Russia to extend the bilateral arms control 

framework to include NSNW. With equal consistency 

Russia has refused to consider these offers. Still, the risk 

posed by this persistent asymmetry in capability was 

manageable during a period in which a nuclear crisis 

seemed a remote possibility. Today, in light of Russia’s 

recent conduct and its continued investment in these 

forces, this possibility is less remote and the risk therefore 

higher. Although the context is different, China’s improved 
nuclear capabilities, which feature modern, theater-range 

nuclear systems, may lead to similar risks. Accordingly, 

mitigating these risks is now a priority, though it does not 

require matching Russia’s large, diverse NSNW capabilities. 

It does, however, require conveying, to Moscow in 

particular, that absent a viable arms control approach, the 

United States will take steps to develop and field a 

capability that lessens our strategic vulnerability, tangibly 

strengthens our regional deterrence posture, and ensures a 

credible response to any nuclear escalation.

SLCM-N Will Play an Important Role in Tailored 

Deterrence Strategies

While the disparity in NSNW in Europe is troubling on 

its own, of greatest concern is the marriage of Russia’s 

large, modern, and diverse nonstrategic nuclear force to a 

military doctrine that seems to allow for the use of nuclear 

weapons on a limited scale to protect Russian gains in a 

local aggression and deter an effective NATO response. 

Russian leaders might execute such a strategy if they 

believed it was their best chance to terminate or freeze a 

conflict on favorable terms—and that the United States

and NATO would be constrained in responding 

proportionately because most available nuclear options 

carry a high risk of further, unintended escalation or could 

be defeated by Russia’s growing anti-access/area denial 

(A2/AD) capabilities. This would be a high-risk approach, 

but Russia’s leaders could conclude the risk is acceptable if 

the stakes were sufficiently high and they believed they 

enjoyed “escalation advantage” at the nonstrategic nuclear 

level.

Based on everything we know, this is a credible 

scenario. To be sure, we understand that the exact 

elements of Russia’s nuclear doctrine are subject to public 

interpretation and debate—and that nations like Russia are 

not necessarily transparent in describing their nuclear 

doctrine publicly. Some degree of ambiguity in assessing 

adversary doctrine is the norm, not the exception. 

Therefore, it is not realistic to expect to know with 

certainty or even a high degree of confidence Russia’s 

policy regarding the circumstances that would trigger 

limited nuclear use against NATO.

But it would be irresponsible to base our policy on a 

benign reading of Moscow’s intentions and how Russian 

leaders think about the nuclear threshold and the risks of 

escalation. Regardless of official doctrine, there are simply 

too many other factors leading to the inescapable 

conclusion that Russia is prepared to use force, take risks, 

and leverage its nuclear weapons to advance its security 

goals. Prudence dictates that the United States and its 

allies consider seriously the possibility that Russian leaders 

could see advantage in the limited use of nuclear weapons 

in a failed or failing conflict, or to consolidate gains made 

through a successful local conventional aggression.

The 2018 NPR adopts this prudent stance and outlines 

an appropriate tailored deterrence strategy for Russia. This 

strategy emphasizes ensuring Russian leaders do not 

miscalculate the consequences of a limited initial use of 

nuclear weapons against NATO and understand clearly that 

a policy of nuclear escalation will yield no significant 

advantage and carry grave risks. SLCM-N directly supports 

this tailored deterrence strategy by providing additional 

limited employment capabilities that an adversary will have 

to consider if contemplating the coercive use of nuclear 

weapons. The availability of such systems will give an 

adversary pause, especially if paired with other 

demonstrations of U.S. and allied resolve, and thus lessen 

the risk of a catastrophic miscalculation. If a crisis 

escalates, leaders will have a wider range of options 

available in the event that the use of nuclear weapons is 

necessary to restore deterrence. Leadership will want 

options that are operationally effective and that signal 

unmistakably the will to defend vital interests and impose 

significant costs on an adversary—but that can be executed 

in a way that is perceptibly restrained and has some 

prospect of managing the risk of further escalation. SLCMN provides such a capability.

The same deterrence logic applies to East Asia, where 

we expect a nuclear-armed SLCM to play an equally 

important role in deterring adversaries and assuring allies. 

The NPR outlines a tailored deterrence strategy for China 

that recognizes its push for regional dominance, its goal of 

countering U.S. power projection operations, its growing 

theater-range nuclear capabilities, and the potential for any 

U.S.-China conflict to escalate to the nuclear level. The 

tailored strategy for China intends to prevent Beijing from 

mistakenly concluding that it could secure an advantage

by, for example, attempting to decouple the United States 

from its allies through the limited use or threatened use of 

its theater nuclear capabilities. SLCM-N conveys a clear 

signal that the United States will maintain graduated 

nuclear employment options that provide the means to 

respond effectively to any level of Chinese nuclear 

escalation.

SLCM-N’s Operational Attributes Reinforce Its 

Deterrence Value
Regional deterrence of both Russia and China requires 

nuclear forces that are responsive, reliable and effective in 

the operational environment likely to characterize a future 

conflict with either power. The credibility of regional 

nuclear forces as a deterrent lies not simply in their 

existence but in their known ability to conduct operations 

that will impose unacceptable costs on a nuclear aggressor. 

This is why the NPR outlined a requirement for a theater 

nuclear system capable of proportional, discriminate 

response based on survivable, regionally present platforms, 

and with the necessary range, penetration capability, and 

effectiveness to hold critical adversary targets at risk.

In particular, regional nuclear systems must be able to 

operate effectively in the face of Russian and Chinese 

A2/AD strategies intended to deny U.S. forces the freedom 

of action to project power and hold adversary operations 

and territory at risk. Given the major investment both 

Russia and China have made in A2/AD capabilities 

(especially advanced integrated air defense systems), each 

may come to believe it can effectively impede U.S. regional 

nuclear capabilities in executing their deterrence missions, 

and thereby secure an exploitable coercive advantage. 

Dual-capable aircraft may be vulnerable, or perceived as 

vulnerable, to advanced defensive systems despite 

enhancements to their stealth and standoff features. As 

defensive systems continue to improve, there is a risk a 

potential adversary may believe it can constrain U.S. ability 

to respond in a proportional manner to limited nuclear use 

and that the United States would be deterred from a more 

escalatory response by the adversary’s withheld nuclear 

capabilities. 

This is why SLCM-N is an important capability. Based 

on highly survivable undersea platforms, SLCM-N will 

reinforce the credibility of tailored deterrent options in 

both European and East Asian contingencies. Sea-based 

systems can exploit an extensive operating area in which 

they will be difficult to find and destroy, preserving the 

ability to respond in a timely way to nuclear aggression 

even if other nonstrategic systems are degraded. In this 

way, SLCM-N will add to the flexibility and diversity of 

regional deterrence forces and provide an assured and 

prompt response capability in demanding operational 

environments.

Promptness is an important consideration. 

Employment options that use the air leg of the Triad 

generally are not considered prompt; they require time to 

 

generate and reach the target or launch point. Some timesensitive, high-priority targets may disperse or launch prior 

to the arrival of an air asset, potentially making U.S. 

deterrent threats less credible. Regionally present seabased systems require far less notice. Operating at a high 

level of readiness, SLCM-N could strike a target quickly 

once the order to execute is received. The adversary could 

not be assured that its high-value mobile strike systems are 

immune to attack, or that a U.S. response to limited 

nuclear use would be delayed. This contributes to 

deterrence credibility.

Finally, a nuclear-armed SLCM force would help to 

hedge against the possibility of (i) a major technical or 

operational failure of the SSBN force or another leg of the 

Triad, and (ii) a significant Russian breakout from arms 

control limits or a Chinese decision to rapidly expand its

nuclear forces. In this way, SLCM-N would enhance the 

overall reliability and survivability of the U.S. nuclear 

posture while also supporting tailored deterrence 

strategies.

SLCM-N Provides Unique Political and Operational 

Benefits in the Indo-Pacific Region

In this vast region, we do not permanently station 

nuclear-capable forces, but rely instead on systems based 

in or rotating from the continental United States. For many 

years the now-retired Tomahawk Land Attack MissileNuclear (TLAM-N) made an important contribution to 

assuring regional allies and underwriting our extended 

deterrence strategy. The ability to provide a regional 

nuclear presence signaled a high degree of resolve and 

readiness in a crisis and did not require allies to base 

nuclear systems on their territory. Restoring that capability 

with SLCM-N will bolster allied confidence in U.S. nuclear 

security guarantees and strengthen our comprehensive 

extended deterrence framework for the region, which also 

includes non-nuclear strike capabilities, missile defense, 

exercises and consultation, and the capability, if needed, to 

forward deploy nuclear-capable bombers and tactical 

aircraft. As former Under Secretary of Defense for Policy 

James Miller and former Vice Chairman of the Joint Chiefs 

of Staff Admiral Sandy Winnefeld (USN, Ret.) have argued 

in reference to SLCM-N, “Such a capability not only would 

provide a credible and survivable option for extended 

deterrence in Europe, but also would bolster deterrence 

and assurance in the Pacific.”3
The existing U.S.-Russia strategic arms control 

framework, the New START Treaty, does not limit sealaunched cruise missiles or their launchers.4

 While it is 

conceivable that a future framework could capture these 

capabilities, this does not seem a realistic basis for planning 

in the current political environment.

The United States is hopeful that its stated intention 

and concrete plans to develop and field SLCM-N will lead 

Russia to conclude that its interests are best served by 

discussing reductions to or limits on nonstrategic nuclear 

weapons. Witnessing U.S. resolve to buttress its deterrent 

forces with a credible, effective capability that can hold 

important Russian military targets at risk could influence 

the thinking of Russian leaders. The history of U.S.-Russia 

nuclear arms control demonstrates that Moscow will 

engage in serious negotiations only when it faces military 

capabilities that match or exceed its own and that can 

impose severe costs. At present, Russia’s leaders see no 

compelling reason to negotiate on NSNW. In the absence 

of concrete steps by the United States to bolster its 

deterrence forces to begin to offset Russian advantages in 

this category of weapons, Russia is unlikely to change its 

approach. U.S. policy remains unchanged: should Russia 

agree to discuss NSNW, and moderate its destabilizing 

behaviors, it may be possible to reconsider the need for 

SLCM-N. But we are realistic about the prospects for this 

outcome.

SLCM-N will not affect the central deterrence 

relationship between the United States and Russia or the 

balance between the two side’s strategic nuclear triads. 

These remain defined by the principles of mutual 

deterrence, the aforementioned New START agreement 

(as long it remains in force), and nuclear risk reduction 

measures (e.g., crisis communications mechanisms). 

SLCM-N will not be based on a strategic nuclear platform 

and will not be subject to the New START Treaty limits. 

SLCM-N will not have intercontinental range. In addition, 

the destructive power and range of U.S. SLCMs—even if 

launched as a salvo—would not threaten the ballistic 

missile forces of major nuclear powers. It is a nonstrategic 

capability that will not threaten the survivability, or 

 

otherwise affect the second strike capability, of an 

adversary’s strategic deterrent forces.

Challenge: SLCM-N responds to a problem that likely 

does not exist or is overstated.

Response: There is indeed an asymmetry in U.S. and 

Russian forces and doctrine, and evidence that Russia has 

acted to widen and exploit it. Our concern is that these 

gaps in capability and approach are from Russia’s vantage 

highly dynamic—not a static phenomenon but something 

that provides an exploitable advantage in crisis or war. This 

could shape the course of regional conflict in a profoundly 

destabilizing way with a high degree of nuclear escalation 

risk. This gap therefore has important implications for preand intra-war deterrence, and also for extended deterrence 

and the assurance of allies. The contention offered by 

some that this gap has been created as a result of our 

talking about it defies common sense. It will not disappear 

if we simply stop referring to it. It will only begin to close 

when we take actions that work to close it. If we ignore it, 

it will get worse and risks will grow.

More fundamentally, deterrence is concerned with 

shaping the adversary’s perceptions and calculations of 

risk. Determining the capabilities required for deterrence 

cannot rely solely on our own sense of what is sufficient 

with respect to the size or cost of a force. To avoid the 

dangers of mirror imaging, we must consider how 

adversaries are likely to view the robustness of U.S. forces, 

applying the standards, criteria and metrics the adversary 

might apply based on what we can learn from doctrine, 

exercises, training, and leadership statements. We must do 

this even if it challenges our own assumptions. A force that 

many might consider comprehensive and sufficient for 

maintaining deterrence even in very challenging 

contingencies may be viewed differently by adversaries 

prepared to take risks and in constant search of exploitable 

advantages derived from perceived or actual asymmetries 

in capabilities and doctrine. If an adversary appears to 

believe such advantages exist or can be created, it is a 

strong signal that our deterrent posture needs to be 

strengthened in a way that the adversary understands 

unambiguously. 
Challenge: SLCM-N is a nuclear warfighting capability 

that will lower the nuclear threshold and make nuclear war 

more likely.

Response: The United States deploys nuclear 

weapons to deter attacks on itself, its deployed forces, and 

its allies and partners. Our nuclear strategy is not premised 

on preparation for or expectation of extended nuclear 

exchanges with an adversary. Strategy, doctrine, forces, 

and exercises all attest to this. The United States maintains 

a high threshold for nuclear use and would use nuclear 

weapons only in an extreme circumstance. All Nuclear 

Posture Reviews, including the current one, have been clear 

on this point. The fact that SLCM-N adds to the options 

leadership has for the limited use of nuclear weapons to 

restore deterrence is not a departure from past policy and 

practice. For decades the United States has maintained 

selective use options and has continually assessed the 

credibility of these options in light of changing strategic 

and operational conditions. The decision to pursue SLCMN simply reflects our current assessment of what is 

required to ensure stable deterrence going forward.

Challenge: SLCM-N will lead to or accelerate a nuclear 

arms race. 

Response: The United States is doing nothing to 

encourage a new arms race in nonstrategic nuclear 

weapons. SLCM-N (as is the low-yield SLBM) is a modest 

response to Russia’s comprehensive program to modernize 

and expand its broad, multi-domain suite of NSNW. It is 

not our goal to match Russia’s deployments. Our purpose 

is to strengthen deterrence and reduce the risks associated 

with what will continue to be an imbalance in NSNW. The 

United States has long sought to advance this objective by 

extending the arms control regime to account for NSNW, 

but has repeatedly been rebuffed by Russia. It is possible 

that our decision to develop and field SLCM-N will give 

pause to Russia’s leaders and lead them to reconsider their 

opposition to negotiated NSNW limits or reductions. 

However, should this materialize and should Moscow in 

tandem take other important steps to promote stability, it 

may be possible to reconsider the need for SLCM-N.

Challenge: SLCM-N operations will detract from 

conventional operations.

Response: Potential tradeoffs with conventional 

operations will be addressed as the programmatic options 

for SLCM-N are evaluated, the number of required 

weapons is defined, and a concept of operations is 

developed. Before these factors are fully examined, it is 

difficult to assess possible tradeoffs. There is no basis 

today to conclude that SLCM-N operations will unduly 

degrade other naval missions. Our expectation is that 

platforms will have capacity to deploy a large number of 

cruise missiles, and that other naval platforms not assigned 

the SLCM-N mission will be able to deliver a significant 

amount of conventional firepower.

Challenge: How is DoD rapidly developing a modern 

SLCM-N?

Response: The development of SLCM-N will follow the 

Joint Capabilities Integration and Development System 

(JCIDS). The Navy has published an Initial Capabilities 

Document (ICD) to identify the attributes of a system to fill 

the requirement identified in the NPR. OSD’s Office of 

Cost Assessment and Program Evaluation (CAPE) has 

provided initial and supplementary guidance for a SLCM-N 

Analysis of Alternatives (AoA) study. The AoA guidance 

encompasses a full range of alternatives, but focuses effort 

on likely solutions to provide the best opportunity to 

establish funding in the FY 2022 budget request with the 

strongest of the alternatives.