In 2022, when Russia launched its full-scale war in Ukraine, the Kremlin’s strategic thinking was shaped around several core ideas. It viewed the United States as its principal geopolitical rival, an adversary that had encouraged Kyiv to impose strategic defeat on Moscow. It considered Europe and NATO largely as an extension of American power. And it saw nuclear muscle flexing as efficient means to exert coercive pressure.
Today, after nearly five years of war, and 22 months of the second Trump administration, the mental map guiding Russian strategy has changed. First, Russia now sees Europe, instead of the United States, as its principal geopolitical adversary, a shift that has driven Russia’s defense establishment to call for an approach known as “castling” to deal with the main threats. Related to this, Moscow now attributes new strategic agency to Europe itself because of the dramatic military modernization taking place in many European countries and the growing interest among some European leaders in developing or extending their own nuclear deterrent. A third shift concerns Russia’s theory of deterrence: Moscow’s traditional understanding of nuclear coercion is giving way to new thinking about nonnuclear strategic deterrence using advanced conventional weapons systems aimed at Europe.
These new lines of thought, which have gained prominence among influential defense intellectuals and policy experts close to the Kremlin over the past year do not need to be endorsed in formal security doctrine to matter. As the past decade has shown, ideas circulating within Russia’s national security establishment have shaped how officials frame problems, define options, and ultimately make major strategic choices. The three recent shifts in Russian strategic thinking will likely play an important part in how Moscow approaches any negotiation to end the war, as well as how it manages future escalation and competition with Europe and the United States.
As the Trump administration steps up its efforts to engage Moscow, it is now negotiating with a Russian leadership whose strategic mindset has evolved considerably since 2022. For the United States, understanding Russia’s new mental map will not only be crucial to any attempt to find an off-ramp with Moscow. It will also be essential to reducing the risk of inadvertent escalation between Russia and Europe and to ensuring strategic stability on the continent in the years to come.
The Pivot To Europe
One of the most notable trends in Russian strategic thought over the past year has been the emergence of the idea of “castling.” A term borrowed from chess, castling in geopolitics describes the repositioning of forces and resources to optimize a state’s strategic posture. Moscow’s defense experts have used the concept to describe a strategy for dealing with a new reality: for the first time since World War II, they have argued, Europe, rather than the United States, has become Russia’s principal geopolitical adversary. According to this view, European countries are now the principal source of Ukraine’s military capacity, political resolve, and strategic resilience; it is Europe and not the United States that has made Ukraine its proxy and is encouraging Kyiv to pursue Moscow’s strategic defeat.
As a consequence, Moscow must direct coercive pressure at Europe—its elites, its decision-making centers, and its critical infrastructure. By doing so, Russia can instill into Europe’s calculus what theorists in Moscow call a “deterring fear”: a European reluctance to antagonize Russia through further support to Ukraine. Such action, they argue, can also rebuild Russian credible deterrence for long-term competition with the West, which is now centered on Europe.
Castling does not imply a change in Russia’s overall objectives, which remain the same as those invoked by Russian President Vladimir Putin at the time of the 2022 invasion. These include banning NATO enlargement to Ukraine and other former Soviet republics; rolling back NATO’s eastern flank; and restricting NATO military exercises, as well as the conventional and nuclear deployments of NATO members, near Russian borders. The difference is that Russian coercion must now be aimed at Europe rather than the United States to achieve these objectives.
Along with this revised assessment of Europe, Russian strategists have interpreted the Trump administration’s own strategic stance as evidence that Asia has replaced Europe as the principal theater of U.S. strategic competition. They point to the administration’s reluctance to back Ukraine, its desire to terminate the war, and its continued overtures to the Kremlin. The administration’s decision in mid-October to provide sanctions relief to Russia and apply new pressure on Ukraine amplify this view in Moscow. Russian strategists also assume Washington seeks to solidify its control of the Western Hemisphere and views China, not Russia, as its primary long-term adversary.
Moscow believes that Washington is thus seeking to reduce its commitments in secondary theaters—particularly Europe and the Middle East—in order to concentrate political, military, and organizational resources on Beijing. As Russia sees it, the new American assertiveness in Venezuela, Cuba, and the Caribbean is unsurprising. By contrast, the current war in Iran—the biggest U.S. military engagement in recent years—has been read in Moscow as an unintended deviation from the new direction of U.S. policy, one that Washington seeks to correct as soon as possible. Whether this reading reflects actual American intentions matters less than that it has become a prevailing understanding in Moscow.
NUCLEAR CURIOSITY
A related trend in Russian discourse is a growing fixation on what defense experts refer to as Europe’s “nuclear curiosity” and new military assertiveness near Russian borders. Specifically, Russian strategists have been concerned by the French and British governments’ modernization of their nuclear programs and apparent readiness to wield them more assertively. Moscow has also noted the prospect of French or British nuclear guarantees extending to European states and nonnuclear European capitals considering the development of nuclear options of their own.
Russian sources identify Germany, Poland, and the Nordic-Baltic states as “nuclear curious,” whether in pursuing nuclear-threshold status or seeking protection under French and British nuclear umbrellas. In this regard, comments by Polish officials in early 2026 expressing support for a Polish nuclear deterrent have been particularly noted. Russian strategists have also closely monitored discussions by Paris and London about offering extended deterrence to the continent as an alternative to the U.S. umbrella.
From Moscow’s perspective, any new attempt by a European state to become a nuclear power would cross a redline and could potentially create a casus belli. Moreover, Europe’s growing assertiveness on nuclear issues is happening in parallel with the deployment of conventional deep-strike precision weapons near Russian borders. For NATO, this more active European posture mitigates the risk of Washington shifting away from its European allies, but to Moscow it signals that Europe could potentially undertake strikes aimed at disarming Russia’s nuclear arsenal or decapitating its leadership.
To Russian analysts, these various developments also suggest Europe’s growing strategic autonomy from the United States. Traditionally, Moscow has viewed Europe largely as a “parking lot” for U.S. forces: a region of the world that is relevant but strategically subordinate to Washington. That assumption is changing. Along with the perception that Europe is now Russia’s principal geopolitical adversary, the continent’s increasing strategic autonomy, including on both nuclear and conventional issues, has become a crucial variable in Russia’s calculus. According to Moscow’s defense intellectuals, Russia may need to change its posture to contain this trend, including by seeking new tools to keep Europe at bay and to coerce it below the nuclear threshold.
MENACING GESTURES
To align with Russia’s new mental map, Russian defense intellectuals and military officers have been examining how to make Moscow’s coercive threats more effective. During the first years of the war, Russia’s nuclear muscle flexing and hybrid warfare failed to prevent Ukraine’s allies from funneling financial support, military aid, and targeting intelligence to Kyiv. This approach also failed to deter Ukraine’s land incursions into Russia and strikes on symbolic Russian targets and Russian strategic infrastructure, let alone compel Kyiv to surrender.
Today, NATO is preoccupied with Russia’s escalating cross-domain coercion, or what U.S. and European analysts call hybrid warfare. But that is only one part of the Russian approach. As Moscow concentrates on Europe as the new primary threat, it is also drawing on new tools of coercion that Russian experts call nonnuclear strategic deterrence. For Russian military authors, NNSD involves using advanced conventional capabilities, including precision-guided weapons, drones, ballistic, cruise, and hypersonic missile systems, as well as “weapons based on new physical principles”—a Russian catchall term for electromagnetic-pulse and high-power microwave weapons to deter and compel adversaries.
Conceptually, NNSD belongs to what Russian experts refer to as the “art of strategic gestures,” a euphemism for using, or threatening to use, nuclear and nonnuclear capabilities to deter and coerce an adversary. The concept is not new. Since the early years of this century, Russian strategists have tried to develop conventional alternatives to nuclear deterrence. But until the full-scale war in Ukraine began, in 2022, these ideas remained underdeveloped. NNSD has emerged from the lessons learned during the conflict.
The Kremlin regards Ukraine as part of a broader struggle over Europe’s strategic order.
From the outset of the war, Russia used tactical ballistics, cruise missiles, and hypersonic capabilities, which it has paired with drones and maneuver warfare. But even when coupled with the threat of nuclear coercion, this approach underdelivered, in the view of many Russian analysts. As a result, as the war has become entrenched, in particular since 2024, Moscow has shifted its focus to more advanced ballistic salvo waves, including strikes using Russia’s intermediate-range Oreshnik ballistic missile.
Drawing on this experience, Russian military theoreticians center NNSD on using massive, deep, precision strikes against the adversary’s critical military, political, and economic infrastructure. The strategy, they suggest, should be aimed not only at Ukraine but also at its European supporters. Although the exact contours of NNSD are still emerging, the concept appears to be more escalatory than the hybrid warfare and deniable asymmetric campaigns that Russia is currently pursuing in Europe.
This is more than a peripheral theoretical discussion. There are already indications that NNSD has gained traction among Russia’s senior military officers: for example, since 2025, the flagship journal of Russia’s general staff, Military Thought, has published several articles on the subject. All the branches of the Russian military are also developing their own versions of NNSD and are seeking to claim a comparative advantage in its execution. This interservice competition may increasingly normalize what constitutes acceptable coercion below the nuclear threshold and shape targeting priorities, as well as escalation management.
THE COERCION THRESHOLD
As the Kremlin sees it, the war in Ukraine began as an attempt to impel Europe to reshape its security architecture. Yet the strategic landscape confronting Moscow today may look even more threatening than the one it sought to change in 2022. Washington needs to recognize that the Kremlin regards Ukraine not as a discrete conflict but as part of a broader struggle over Europe’s strategic order. Any U.S.-led effort to broker an off-ramp in Ukraine will need to reckon with Moscow’s emerging castling logic and its mounting anxieties about Europe. A settlement that addresses the immediate battlefield while leaving Moscow’s wider frictions with Europe untouched is likely to provide only a temporary pause in this larger conflict. Washington needs to understand that Russia’s nonnuclear coercion has become a part of its ongoing deterrence strategy against Europe rather than simply a feature of the war itself.
Even if Moscow engages in negotiations to end the war, it is likely to continue using military coercion against Ukraine, as well as Europe. It will do so for several reasons: to align the terms of the settlement with Russian interests, to refine Russia’s emerging theory of nonnuclear strategic deterrence, and to force Europe to adopt a different security architecture. Russia may therefore undertake precision strikes on critical infrastructure, and even possible decapitation attempts, as well as calibrated attacks of varying intensity in Ukraine, alongside diplomatic engagement. By using such tactics, Moscow will be seeking not only to gain leverage in negotiations with Kyiv but also to restore its strategic deterrence with Europe. In response, Europe, doubting the credibility of the Trump administration’s commitments and seeking to demonstrate its own resolve, may decide to escalate.
Washington should thus be prepared for the possibility that stepped-up efforts to terminate the war may coincide with heightened security risks in Europe. Given that the dynamic between Europe and Russia is now characterized by pervasive mutual suspicion, conspiracy theories, and expectations of war, there is a growing danger of inadvertent escalation. Actions by either side that are intended as limited coercion, signaling, or leverage might be misread, thus triggering a self-reinforcing action-reaction cycle in which each side’s effort to restore deterrence instead erodes it. Paradoxically, this dynamic could emerge precisely at the moment when all sides—including the Kremlin—are seeking an off-ramp. Both Europe and Russia risk crossing a “culmination point of coercion,” beyond which any additional threats to use force, or its actual use, could expand the war further.
For Russia and Europe, then, the main challenge will be to bolster deterrence without crossing this tipping point. For Washington, the primary task is not only to mediate the substance of a deal but also to learn how to choreograph negotiations amid ongoing military action. It will be imperative for U.S. officials to anticipate coercive moves by all sides without mistaking them for a rejection of diplomacy—and without allowing them to derail negotiations. Washington will need to help both Europe and Russia contain their use of coercion before the security dilemma locks them into a dangerous escalatory spasm.
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