Nuclear Signalling and the Shadow of Escalation in the Ukraine Conflict

Since the outbreak of Russia’s full-scale invasion of Ukraine in February 2022, the spectre of nuclear weapons has loomed over the conflict. While no nuclear weapons have been used, Moscow’s repeated nuclear rhetoric and military posturing have revived Cold War anxieties and introduced a complex layer of strategic ambiguity into the war. Nuclear signalling—deliberate actions or statements intended to convey the possibility of nuclear use—has become a central tool in Russia’s efforts to deter Western military support for Ukraine and to manage escalation on its own terms. Here we explore the function of nuclear signalling in the Ukraine war, the risks it presents and the constraints on nuclear escalation, drawing upon historical precedent, strategic theory and current international dynamics.

The Logic of Nuclear Signalling

Nuclear signalling operates as a form of coercive diplomacy. It aims to influence an adversary’s calculations by introducing the risk—real or perceived—of a nuclear response. In the context of Ukraine, Russia has employed nuclear rhetoric to deter NATO intervention and to raise the potential costs of continued Western support to Ukraine. Such signalling has included public references to Russia’s nuclear arsenal by President Vladimir Putin and other officials, the ostentatious movement of nuclear-capable systems, and exercises involving strategic forces.

Russian military doctrine explicitly includes the possibility of nuclear use in response to existential threats, even in a conventional conflict. This doctrinal ambiguity allows the Kremlin to blur the lines between conventional and nuclear warfare, creating what some analysts have termed an “escalate to de-escalate” posture—whereby Russia might use a limited nuclear strike to force a favourable political settlement.

Russia’s Use of Nuclear Rhetoric Since 2022

Since February 2022, President Putin and other senior Russian officials have repeatedly invoked the nuclear option. On the first day of the invasion, Putin warned that any foreign interference would result in “consequences you have never seen in your history”. In the months that followed, Russian nuclear-capable units were put on alert and strategic exercises were showcased on state media.

Particularly during periods when Ukraine has regained territory—such as during the Kharkiv counteroffensive in autumn 2022 or the November 2022 liberation of Kherson—Russia escalated her nuclear rhetoric. In September 2022, after the formal annexation of four Ukrainian regions, Putin declared that Russia would use “all means necessary” to defend her territory, widely interpreted to include nuclear weapons. Similar threats have been issued around the Ukrainian campaign in Crimea and the intensification of Western arms transfers.

The NATO Response and Strategic Restraint

In response, NATO and Western leaders have adopted a policy of strategic calm. Rather than mirror Russian rhetoric, Western statements have aimed to de-escalate and deny Moscow the narrative that it is responding defensively to Western aggression. US President Joe Biden warned of “Armageddon” in October 2022 if Russia crossed the nuclear threshold, while his administration reportedly communicated clear red lines and consequences to Moscow through backchannels.

This restraint has served to maintain alliance unity and limit the risk of inadvertent escalation. The use of military aid—such as long-range missile systems—has been calibrated carefully to avoid crossing perceived thresholds that might provoke Russian escalation. Notably while Western countries have increased the range and sophistication of their support, they have refrained from directly deploying forces in Ukraine or providing weapons capable of striking deep into Russian territory—at least officially.

The Shadow of Escalation: Risks and Limits

The central danger posed by nuclear signalling is miscalculation. If either side misinterprets intentions or thresholds, escalation could spiral out of control. This is particularly dangerous given the degraded state of arms control regimes between Russia and the West, the limited military-to-military communication, and the politicisation of nuclear weapons in Russian domestic propaganda.

However, several factors have thus far constrained escalation:

• Nuclear taboo: The use of nuclear weapons remains heavily stigmatised internationally, including among Russia’s few remaining allies such as China and India, who have signalled their strong opposition to nuclear use.

  
  

• Military impracticality: It is unclear what military advantage Russia would gain from use of tactical nuclear weapons in Ukraine, given the dispersed nature of Ukrainian forces and their proximity to Russian troops.

  
  

• Strategic consequences: Any nuclear use would risk massive diplomatic isolation, possible direct NATO intervention, and long-term consequences for Russia’s global position and even existence.

In effect Russia’s nuclear threats have served more as a shield than a sword: they have helped deter Western overreach but have not achieved decisive results in halting Ukraine’s resistance or Western support.

Escalation Scenarios and the Path Forward

Looking forward, several scenarios could trigger more dangerous nuclear brinkmanship. These include a major Ukrainian breakthrough in Crimea, a perceived threat to the Russian regime’s survival, or an internal crisis that incentivises external distraction. Conversely Russia’s reliance on nuclear signalling may decline if the war becomes more entrenched or if Russia consolidates gains diplomatically.

The West faces the challenge of maintaining support for Ukraine without giving Moscow a pretext to escalate. This involves balancing deterrence with assurance, reinforcing the credibility of nuclear deterrence (i.e. spending more money on nuclear weapons, creating another arms race) while at the same time working to restore arms control channels so that the Russians appreciate that nuclear arms control negotiations are the only way out of a second arms race they cannot hope to win.

Meanwhile Ukraine’s strategy includes demonstrating resilience, minimising civilian exposure and diplomatically isolating Russia. Nuclear threats have not deterred Ukraine’s will to fight, but they complicate the task of war termination and post-war security guarantees.

Conclusion

Nuclear signalling in the Ukraine conflict reveals the enduring dangers of nuclear weapons in conventional wars involving nuclear-armed states. While the nuclear shadow has so far remained just that—a shadow—it has shaped the war’s parameters and introduced new levels of risk to global security. The measured response by NATO, the deterrent effect of the nuclear taboo, and the international consensus against nuclear use have thus far prevented catastrophe. However, as the war continues into its third year and beyond, managing the risks of nuclear escalation will remain a central and complex feature of the strategic landscape. The path to peace must navigate not only the trenches of Ukraine but the nuclear thresholds that lurk above them.

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Reading List

Academic and Strategic Theory Sources

1. Schelling, Thomas C. – The Strategy of Conflict (1960)

   • A foundational work on deterrence theory, coercion, and the role of signalling in conflict.

   
   

2. Freedman, Lawrence – Deterrence (2004)

   • Offers a comprehensive modern review of deterrence, including nuclear deterrence and escalation management.

   
   

3. Payne, Keith B. – The Fallacies of Cold War Deterrence and a New Direction (2001)

   • Challenges conventional deterrence theory and introduces the notion of tailored deterrence strategies.

   
   

4. Acton, James M. – “Escalation through Entanglement: How the Vulnerability of Command-and-Control Systems Raises the Risks of Inadvertent Nuclear War” – International Security (2018)

   • Analyses how technological and strategic interdependencies could lead to unintended escalation.

   
   

5. Narang, Vipin – Nuclear Strategy in the Modern Era: Regional Powers and International Conflict (2014)

   • Useful for understanding how regional nuclear powers behave differently from Cold War superpowers.

   
   

Policy and Analytical Reports

6. Arbatov, Alexei – Understanding the U.S.-Russia Nuclear Schism – Carnegie Moscow Center (2019)

   • Offers insight into divergent Russian and Western nuclear doctrines.

   
   

7. Lewis, Jeffrey & Pomper, Miles – Russia’s Nuclear Threats Are a Bluff—But a Dangerous One – Foreign Policy(2022)

   • Argues that Russia’s nuclear rhetoric is unlikely to translate into use, while still posing risks.

   
   

8. Pifer, Steven – Nuclear Arms Control After Ukraine – Brookings Institution (2023)

   • Discusses the breakdown of arms control regimes and the implications for European security.

   
   

9. Kroenig, Matthew – The Return of Great Power Rivalry: Democracy versus Autocracy from the Ancient World to the US and China (2020)

   • Not Ukraine-specific, but includes chapters on nuclear strategy and great power conflict.

   
   

10. International Crisis Group – Managing Escalation Risks in the Russia-Ukraine War (2023)