A close reading of Russia’s nuclear statements and actions during the first seven months of its war against Ukraine reveals a threefold approach. Moscow is walking a fine line between a well-crafted and successful deterrence strategy to prevent foreign military intervention; a more modest and rather unsuccessful attempt at dissuading foreign aid to Ukraine and sanctions against Russia; and incremental nuclear coercion against Kyiv that spurred Western deterrence messaging in response. This analysis reveals a careful Russian approach, suggesting that cost-benefit calculations are likely to continue to render nuclear escalation unlikely. However, nuclear use cannot be fully discounted, particularly if war-related developments severely imperil the survival of Russia’s regime.
Seven months after Russia’s full-scale invasion of Ukraine, casual observers surmise that the Kremlin has been threatening to use nuclear weapons extensively and recklessly. Given both Moscow’s rabid war fighting methods and its convoluted nuclear signaling, this perception is understandable – but nonetheless mistaken. On the basis of an extensive SWP chronology of nuclear interactions throughout the war, it is possible to conclude that Russian rhetoric has been carefully calibrated to deter foreign military intervention; dissuade foreign aid to Ukraine; and coerce the government in Kyiv.
Russia’s deterrence success
From February to September 2022, policymakers in Moscow repeatedly stated that any clash between NATO and Russian forces would risk nuclear war. Hence, throughout the past seven months, most Russian nuclear narratives were geared towards deterring both democratic decisionmakers and the Western electorate from even considering a direct military intervention in Ukraine. Thus, Moscow primarily employed nuclear threats to create a sanctuary against foreign military involvement – a red line the West neither crossed, nor questioned. President Vladimir Putin laid the groundwork on February 24, the day of Russia’s full-scale invasion: Those “tempted to interfere” from “the outside” would face a response never seen in history, he declared. Subsequently, this position was repeated by Russian officials more than half a dozen times, including twice by Putin and twice by Foreign Minister Sergey Lavrov.
To this limited end, Russia’s nuclear deterrence was successful. Most in the West concluded that a direct military intervention was not warranted, though whether this was because, or irrespective, of Moscow’s nuclear rhetoric or even its atomic arsenal remains impossible to determine. Western policymakers mirrored Russia’s red line, categorically excluding the possibility of a direct military confrontation. For instance, mere hours after Putin’s threat, US President Joe Biden stressed that American forces would “not be engaged in the conflict with Russia in Ukraine,” and during the first month after the full-scale invasion, Western representatives reiterated this position almost every other day. Echoing Russian rhetoric, they repeatedly explained this non-intervention stance by citing escalation risks. Tellingly, the only context in which Western officials alluded to the possibility of a direct intervention was in case Russia used nuclear weapons – a scenario in which the deterrence threat would have already been executed. Conversely, even the use of chemical weapons by Russia would not trigger an intervention, said US officials.
In contrast, whenever Western politicians merely alluded that armed intervention might potentially become an option, Russian policymakers renewed their explicit warning. For example, UK Foreign Secretary Liz Truss noted on February 27 that the West needed to stop Russia in Ukraine to protect other countries from being threatened – a development that might lead to a “conflict with NATO.” Russian officials responded swiftly – whether solely to British statements or also to other Western signals remains unclear. Putin ordered a “high combat alert” for Russia’s strategic forces, condemning alleged “aggressive” Western declarations. Later, at least half a dozen Russian statements explicitly denounced Truss’s comment or linked the Kremlin’s nuclear narratives to supposedly aggressive Western rhetoric.
This deterrence dynamic reoccurred at least twice. In March, Ukrainian President Volodymyr Zelenskyy urged Western countries to establish a no-fly zone over Ukraine, which arguably would have required NATO forces to directly engage Russian assets. Putin immediately warned of “tremendous” and “disastrous” global consequences. A few weeks later, Poland called for a NATO peacekeeping mission in Ukraine. Shortly thereafter, Putin accused the West of wanting to “cancel” Russia and destroy its territorial integrity. Four other statements, including from Lavrov, followed suit, cautioning against a direct clash between Russian and NATO forces, which could lead to nuclear escalation.
Some initial divergent risk assessments notwithstanding, NATO Allies quickly reverted to Russia’s red line. To illustrate, the Polish peacekeeping proposal was initially welcomed by Denmark, but opposed by Germany. Still, all Allies remained cautious and waited for a common position to emerge before taking any concrete steps. In the end, NATO Allies jointly rejected the no-fly zone and peacekeeping proposals, explicitly citing escalation risks and emphasizing that NATO did not want to become a cobelligerent.
Russia’s mixed dissuasion results
While both sides agreed on the need to prevent a direct confrontation between nuclear powers, Moscow went further, attempting to dissuade Western support to Kyiv more broadly. Thus, the Russian leadership alluded that it might increase the risk of nuclear escalation in response to Western military assistance for Ukraine or sanctions against Russia. This dissuasion strategy had very limited success – it did not prevent, but probably slowed down, and maybe also imposed some limits on, military deliveries and sanctions.
Putin’s statement on the day of the invasion was sufficiently vague to be interpreted by many in the West as threatening those who dared to help Kyiv or sanction Moscow. Indeed, Putin subsequently linked his decision to raise the alert level of Russia’s nuclear forces to inter alia the West’s “illegitimate sanctions.” More than a dozen statements by Russian officials followed – warning of the dangers of weapons deliveries, of sanctions, or of “interference” with the “special operation.”
Moscow’s dissuasion attempts were however extremely cautious. First, the nuclear dimension of these statements remained largely implicit. For example, Moscow’s representatives sometimes spoke of sanctions or military assistance in terms echoing Russia’s nuclear doctrine. Aid amounted to an “act of aggression” or created “existential” threats, Russian officials said, thereby alluding to the possibility of a nuclear reaction. Russian policymakers also warned that Western assistance could lead to a dangerous “direct clash,” or had already produced a proxy confrontation – the very scenario both sides agreed was fraught with risks. Second, these implicit threats were followed by a series of explicit denials, corrections, and accusations of “misreading” Russia’s “purely defensive” policies. More than a dozen statements denied that such a dissuasion policy was being pursued at all or asserted that Russia would use nuclear weapons only if it were directly attacked.
NATO states in turn were keen to demonstrate that Russia’s nuclear blackmail was unsuccessful, perhaps trying to prevent the establishment of a dangerous precedent. Throughout the first seven months of the war, Western representatives announced continuous or enhanced support for Ukraine in more than five dozen instances. Such statements occurred at least on a biweekly basis, though often several times per week, and were particularly frequent in the aftermath of Russian nuclear threats – for instance, in late February or in late April.
Despite these declaratory rejections of the effectiveness of Russian dissuasion, Western behavior however denotes a cautious reaction. While it remains impossible to establish whether this was due to Russia’s innuendos or its sheer possession of nuclear weapons, NATO states clearly attempted to calibrate their support to Ukraine to avoid sliding into a direct NATO-Russia confrontation fraught with nuclear risks. Five aspects are central to this cautiousness. First, NATO governments restricted access to information, keeping certain announcement intentionally vague, and confirming certain deliveries only after they had arrived in Ukraine. Second, both Europeans and Americans took an incremental approach towards both the quantity and the quality of delivered weapons, seeking to gauge Moscow’s reaction before taking additional steps. Third, the West repeatedly and publicly refuted Russia’s attempt to conflate the provision of extensive assistance with direct military engagement. Fourth, Western states often erred on the side of caution when possible deliveries were debated publicly, as in the case of fighter jets or certain types of battle tanks. Finally, Western representatives sought to avoid becoming associated with Ukrainian attacks on high-value Russian targets.
Russia’s failed coercion attempts
The possibility that Russia might use nuclear weapons against Ukraine has concerned policymakers in Kyiv and throughout the West, and triggered Western deterrence messaging. It is noteworthy that Russian officials repeatedly denied any such intentions during the conflict’s first few months – at least a dozen statements stressed the defensive posture of Russia’s nuclear arsenal, posited that the local conflict in Ukraine lacked a nuclear dimension, or explicitly declared that such weapons would not be employed against Ukraine. However, at least a handful of concerning allusions – to fictitious Ukrainian nuclear or biological weapons programs or to residual Soviet nuclear delivery capabilities – appeared to suggest to Western ears that Moscow could potentially be creating a pretext to legitimize a nuclear strike against Ukraine in line with Russian doctrine.
In an effort to deter Russia from considering such coercive options and to boost Ukrainian resolve, US and NATO officials responded with a number of increasingly explicit red lines. Though publicly, US officials initially dismissed such options as improbable, Western policymakers warned Russia against nuclear use behind closed doors already in late February. By late April, Western concerns seemed to grow as intelligence analysts emphasized publicly the low probability but high impact nature of this contingency. Against this background, Biden issued a first public warning at the end of April, stressing that the United States was ready for “whatever” Russia might do. A second, more explicit warning came in late May, when Biden declared that “any” nuclear use would be “completely unacceptable” and entail “severe consequences.” Finally, in late June, Washington released a similar warning together with G7 partners.
Apprehensions grew again by September, triggering further Western deterrence messaging. Faced with military setbacks, Moscow decided to formally annex partially conquered Ukrainian provinces and suggested it might use nuclear weapons to protect its “territorial integrity.” In this context, Washington relayed specific warnings to the Kremlin in private, but Biden also cautioned Putin publicly, noting that nuclear use would “change the face of war” and spur “consequential” US reactions. Other US, European, and NATO officials also underlined the “catastrophic consequences” Russia would face.
Over the past seven months, Western officials repeatedly confirmed that, thus far, Russia had made no physical preparations to employ nuclear weapons. Conversely, all internal deliberations in Moscow remain hidden. However, building upon Russia’s observable threefold nuclear strategy, three implications for possible future developments emerge.
First, both Western and Russian statements and actions suggest that the risks of nuclear use would indeed grow if NATO were to intervene with overwhelming force in the conflict – but nothing indicates that the Alliance is going down that route.
Below the threshold of direct intervention, in turn, Western governments seem to have more leeway to aid Ukraine’s war effort than many pundits and policymakers presume. Moscow’s statements and observable behavior do not indicate that the Kremlin is considering employing nuclear weapons in response to military aid to Ukraine or sanctions against Russia – least against NATO members. To the contrary and in line with Moscow’s deterrence strategy, Russian policymakers have been keen to avoid any escalation that could lead to a direct confrontation with the transatlantic alliance. Given the sizable military impact that Western military aid has already had on Russia’s war effort, it appears unlikely that certain types of weapons deliveries would change Moscow’s basic position that a direct clash with NATO states must be avoided.
Finally, the Kremlin’s calculating and cautious approach to nuclear signaling also suggests that, at least for now, its implied nuclear threats against Ukraine remain implausible. If Kyiv’s counteroffensive proves successful in the longer term, however, it seems worthwhile to carefully think through the causal chains that could potentially link a Russian military defeat in Ukraine to regime change concerns in Russia and, hence, to more acute nuclear escalation risks.
Dr Liviu Horovitz is Research Associate, and Anna Clara Arndt is Research Assistant in the International Security Research Division at SWP. This Comment appears within the framework of project STAND (Strategic Threat Analysis and Nuclear (Dis-)Order).
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