The urgent imperative to maintain NATO’s nuclear deterrence

The dismal performance of Russia’s conventional forces in the early days of the war in Ukraine risks convincing some in NATO that the future Russian threat to the Alliance can be deterred primarily via NATO’s conventional superiority, and that enhancing deterrence of Russian nuclear use in a future conflict is therefore no longer a high priority. This is a dangerous fallacy.

(Main photo by US Navy/General Dynamics: PCU Virginia (SSN 774) returns to the General Dynamics Electric Boat shipyard following the successful completion of its first voyage in open seas called “alpha” sea trials)

By Gregory Weaver
Posted in NATO Review

It fails to take into account the relevant lessons learned from Russia’s invasion of Ukraine, and the fundamental change in the future security environment in which NATO will have to deter or defeat Russian aggression and escalation.

So what lessons might NATO and Russian leaders draw from the war in Ukraine? Obviously, this will depend in part on the outcome of the war, which we cannot yet foresee, and could take many forms. This article assumes only that the war in Ukraine will end without Russian nuclear use, and without a decisive Russian victory.

First, NATO leaders should learn that Putin’s decision to invade Ukraine demonstrated both a high propensity to take risk, and to miscalculate profoundly in the process of doing so. That combination of risk-taking and miscalculation is extremely troubling, particularly when paired with Russia’s repeated nuclear escalation threats.

Second, NATO leadership should learn that the performance of Russian forces in Ukraine is likely to lead to increased Russian reliance on nuclear weapons. In a hypothetical future war with NATO, Russia would be likely to perceive the need to use nuclear weapons earlier in the conflict, either to seek victory or to prevent defeat. This means deterring Russian limited nuclear escalation will become even more important than deterring Russian conventional aggression.

Third, NATO’s leadership should not draw the lesson that if Russian leaders do not use nuclear weapons in Ukraine, they will not do so against NATO under other circumstances. There is a tendency among some in the West to make a perilously flawed assumption: that deterrence of nuclear use is unlikely to fail because if nuclear weapons are used at all, in any number or yield, and for any purpose, the war will rapidly escalate out of control to a catastrophic large-scale exchange almost automatically. (It is of course possible that limited nuclear use could lead to uncontrolled escalation, but it is by no means certain and may not even be likely). This flawed assumption may lead to a flawed prescription: to rely primarily on the threat of uncontrolled nuclear escalation to deter Russian nuclear use at any level, ignoring Russia’s strategy, the array of nuclear capabilities that enable it, and the robust stability of central deterrence of large-scale Russia-US homeland nuclear strikes.

Fourth, if Russia’s leadership were to assume that NATO’s unwillingness to intervene militarily in Ukraine is the result of its repeated nuclear threats, Russia will draw the wrong lesson regarding NATO’s will to fight in the face of such nuclear threats in a conflict with the Alliance. This misperception could convince Russia that coercive nuclear threats or use will split the Alliance in a future crisis or conflict with acceptable risk that NATO will not respond in a way that decisively worsens Russia’s position in the conflict.

An ongoing fundamental change in the international security environment is also increasing the importance of NATO’s nuclear deterrent. Due to China’s rapid nuclear buildup, the US and its allies will soon face two nuclear peer adversaries for the first time in the nuclear age. Were China’s new peer status to give them the confidence to attack Taiwan, Russian leaders might see an opportunity for aggression against NATO, given that another nuclear peer may distract the US military. NATO’s current conventional superiority against Russia would be greatly diminished or negated in that scenario, forcing NATO to rely on nuclear weapons to counter Russian conventional superiority. And were Russia to conclude that their theater nuclear weapons advantage provided either decisive military superiority or a trump card in the event such opportunistic conventional aggression against NATO were to fail, a Russia-NATO war could result.

In sum, deterring Russian nuclear escalation will still matter after the war in Ukraine ends for four main reasons:

Russia’s leaders have demonstrated a propensity to take risk and miscalculate in doing so.

Those leaders’ experience in Ukraine may have convinced them that NATO is vulnerable to nuclear coercion.

Russia will likely increase its reliance on nuclear weapons due to the performance of its conventional forces in Ukraine.

Russia could be presented with an opportunity to attack NATO if the US becomes engaged in a major conflict with another nuclear peer.

Deterring Russian nuclear use against NATO will thus remain an urgent imperative, even after the war in Ukraine ends.

The Russian nuclear deterrence challenge

Deterring the use of nuclear weapons by Russia requires an understanding of Russian nuclear strategy, doctrine, and capabilities. The role of Russian nuclear forces is to both deter large-scale nuclear attacks on the Russian homeland and compensate for NATO’s conventional superiority through the limited use of nuclear weapons in theater, to coerce if possible, but to defeat if necessary. Russian strategy is thus rooted in the assumption that limited theater nuclear use is unlikely to escalate uncontrollably to a large-scale US-Russia homeland exchange, making a hypothetical NATO strategy to rely primarily on the threat of uncontrolled escalation extremely risky.

The “coercive” escalation option envisions initiating limited nuclear use to compel termination of a conventional war on terms acceptable to Russia. Given Russia’s recent behavior, NATO must ask itself what might constitute such terms. Before the war in Ukraine began, this option was most often understood to mean coercive escalation to avoid impending conventional defeat. However, Russia’s potentially increased reliance on nuclear weapons in the period following the end of the war in Ukraine may mean coercive escalation could be used to win as well.

The “defeat” escalation option envisions conducting large-scale theater nuclear operations against NATO’s conventional forces if Russian leadership determines that NATO poses a threat to “the very existence of the Russian state”. This is what drives Russia’s force requirement for thousands of theater nuclear weapons embedded throughout their conventional forces. NATO must ask itself what Russian leaders might perceive as constituting such a threat in a hypothetical war with NATO post Ukraine. Once again, in a situation where Russia is more reliant on nuclear weapons, they could perceive their theater “defeat” option as the means to win rather than to avoid losing.

Maintaining NATO’s nuclear deterrence posture: what it will take and why

Given that Russian strategy assumes that the mutual deterrence of large-scale US-Russia homeland strikes is very robust, deterrence of Russian limited nuclear use requires the perceived ability of NATO to persevere in the face of Russian limited escalation without being politically coerced, and without being decisively militarily disadvantaged.

That requires a set of US and Allied nuclear capabilities that enable a credible Flexible Response strategy that convinces Russian leadership that limited nuclear escalation does not provide insurance against miscalculating about NATO’s resolve, will not result in war termination on their terms, and does indeed run the risk of uncontrolled escalation. NATO must be perceived to be fully prepared for what Thomas Schelling called a “competition in risk-taking” that creates a “threat that leaves something to chance”.

To enable that strategy, NATO nuclear and conventional forces must be capable of:

Providing a robust range of response options to restore deterrence by convincing Russian leadership they have direly miscalculated, that further nuclear use will not achieve their objectives, and that they will incur costs that far exceed any benefits they can achieve.

Countering the military impact of Russian theater nuclear use.

Continuing to operate effectively to achieve US and Allied objectives in a limited nuclear use environment.

To meet these requirements NATO needs a range of continuously forward deployed, survivable theater nuclear capabilities that can reliably penetrate adversary theater air and missile defenses with a range of explosive yields on operationally relevant timelines.

Strategic nuclear forces alone are insufficiently flexible and timely to convince Russian leadership that NATO is fully prepared to counter limited nuclear first use with militarily effective nuclear responses of our own. Given Russian strategy, doctrine, and capabilities, and the potential for simultaneous theater conflicts with two nuclear peers, additional NATO theater nuclear capabilities are required.

Modernisation of NATO’s dual capable fighter aircraft capabilities is necessary and ongoing, but not sufficient. NATO’s planned theater nuclear forces are too small, insufficiently survivable, and lack adequate flexibility to address the range of military scenarios we could see from Russia. But they could be greatly improved without having to match Russia weapon for weapon.

NATO should supplement its dual capable fighter capability with at least one more theater nuclear capability that meets the requirements noted above. Several candidate systems could meet this requirement, but a nuclear-armed sea-launched cruise missile (SLCM-N) deployed on US attack submarines provides all the necessary attributes.

To address the potential degradation or negation of NATO’s conventional superiority in the event of Russian opportunistic aggression, it is necessary to improve NATO’s ability to fight and win a conventional war if the US were engaged in a war with China. If such improvements are not made, additional deterrent and warfighting demands will be placed on NATO’s already insufficient nuclear forces.

Because a war over Taiwan would emphasise different US force elements than a war in defense of NATO (primarily naval and air forces in Asia, primarily ground and air forces in Europe) there are steps NATO could take to reduce the impact on the NATO-Russia balance of Europe being the “second theater” in a two theater war. The primary limitation on the ability of the US to engage in military operations in Europe and East Asia simultaneously is logistics: strategic air and sealift and stocks of advanced conventional munitions. There are also key “low density, high demand” American military capabilities that would be in short supply in a two-theater conflict: bomber aircraft, integrated air and missile defenses (IAMD), tanker aircraft, ISR capabilities, and anti-submarine warfare (ASW) capabilities.

NATO could create a more optimised division of labor to compensate for these shortfalls. The US could preposition more heavy ground force equipment and provide more deep precision strike capabilities in Europe. NATO could form a European version of the US Civilian Reserve Air Fleet (CRAF): Allied civilian airliners committed to transport US soldiers to their equipment in Europe while US CRAF supports the Asian theater. European Allies could provide NATO’s IAMD, tanker aircraft to support air combat operations and airlift, improved ASW capabilities, and several modern armored divisions capable of rapidly blunting a Russian invasion of the Baltic States, Poland or Romania.

The bottom line is that European Allies will have to provide more conventional capability more efficiently, without perceiving the US request to do so as signaling a reduced US commitment to the defense of NATO. And the US needs to provide additional theater nuclear capability. Failing to do both will risk opportunistic aggression in Europe, and a war in which NATO will be more reliant on nuclear weapons against an adversary that has a growing theater nuclear advantage.

In the wake of the war in Ukraine, deterring Russian nuclear use is not the place for NATO to take risks. An inability to deter or counter Russian limited theater nuclear use will make both Russian conventional aggression and nuclear escalation against NATO more likely, especially opportunistic aggression by Russia.

(What is published in NATO Review does not constitute the official position or policy of NATO or member governments.NATO Review seeks to inform and promote debate on security issues. The views expressed by authors are their own)

Mr. Gregory Weaver is a retired member of the US Senior Executive Service and the Principal of Strategy to Plans, LLC. He served as a Federal Senior Executive on the US Joint Staff in the Office of the Undersecretary of Defense for Policy, and at United States Strategic Command. In his last government position, he was the principal nuclear, space, cyber, missile defense, and arms control policy, strategy, and plans advisor to the Chairman of the Joint Chiefs of Staff. He was awarded the Presidential Rank Award for Distinguished Executive Service in 2021 and the Department of Defense Distinguished Civilian Service award in 2020.