When Russia launched its full-scale military invasion of Ukraine in 2022, the strategic calculus inside the Kremlin was built upon a specific, clear set of assumptions. At that time, Moscow viewed the United States as its principal geopolitical rival—an overarching adversary that it believed had systematically encouraged Kyiv to pursue a strategic defeat for the Russian state. In this initial framework, Europe and NATO were largely perceived as subordinate extensions of American power, useful mainly as instruments of Washington’s global hegemony. Furthermore, the Kremlin heavily relied on nuclear muscle-flexing as its primary and most efficient mechanism for exerting coercive pressure on the West.
Today, after nearly five years of relentless warfare and nearly two years into the second Trump administration, that foundational mental map has undergone a profound transformation. According to influential defense intellectuals and policy experts close to the Kremlin, the Russian security establishment has fundamentally reevaluated its primary threats. First and foremost, Russia now identifies Europe, rather than the United States, as its primary geopolitical adversary. This dramatic perceptual shift has driven Moscow’s defense planning toward a newly minted strategic concept known as "castling."
Closely tied to this pivot is a growing recognition within Russian military circles that Europe has acquired a newfound strategic agency. This is attributed to the rapid military modernization currently underway in many European nations, alongside a rising interest among certain continental leaders in developing, expanding, or sharing independent nuclear deterrents. Finally, Moscow’s traditional reliance on nuclear coercion is increasingly giving way to a sophisticated focus on nonnuclear strategic deterrence, leveraging advanced conventional weapons systems specifically targeted at European infrastructure.
While these evolving lines of thought do not necessarily require formal endorsement in official security doctrine to carry weight, history shows that ideas circulating within Russia’s national security establishment profoundly shape how officials frame problems, define options, and execute major strategic choices. These three distinct shifts in Russian strategic thinking are destined to play a vital role in how Moscow approaches any future negotiations aimed at ending the war, as well as how it manages long-term escalation and competition with both Europe and the United States.
As the current U.S. administration intensifies its diplomatic outreach to Moscow, it finds itself negotiating with a Russian leadership whose worldview has evolved significantly since the outbreak of the war. For Washington, comprehending this new mental map will be crucial not only for finding a viable diplomatic off-ramp with the Kremlin, but also for mitigating the escalating risk of inadvertent military escalation between Russia and Europe, thereby securing long-term strategic stability across the continent.
The Pivot To Europe
One of the most striking developments in Russian strategic discourse over the past year is the widespread adoption of the concept of "castling." Borrowed directly from the game of chess, the geopolitical term describes the tactical repositioning of forces and resources to optimize a state’s overall strategic posture. Russian defense experts have embraced the metaphor to articulate a new reality: for the first time since the conclusion of the Second World War, they argue, Europe has eclipsed the United States as Russia’s preeminent geopolitical adversary.
From Moscow’s perspective, European nations now constitute the foundational source of Ukraine’s ongoing military capacity, political resolve, and strategic resilience. In the Kremlin’s view, it is Europe—not Washington—that has effectively adopted Ukraine as a proxy and actively encouraged Kyiv to pursue the strategic defeat of the Russian Federation. Consequently, Russian strategists argue that Moscow must redirect its coercive pressure squarely at Europe, targeting its political elites, decision-making centers, and critical infrastructure.
By executing this shift, Russia aims to instill what its theorists call "deterring fear" into European decision-making—fostering a deep reluctance among European leaders to further antagonize Moscow through continued military and financial support for Ukraine. Proponents of castling argue that this approach will help rebuild credible Russian deterrence for a long-term competition with the West that is now fundamentally anchored in Europe.
Crucially, this strategic pivot does not entail a revision of Russia’s core political and military objectives, which remain entirely consistent with the demands laid out by Russian President Vladimir Putin at the time of the 2022 invasion. These goals include permanently barring NATO enlargement to include Ukraine and other former Soviet republics, rolling back the alliance’s eastern military footprint, and sharply restricting NATO military exercises alongside conventional and nuclear deployments near Russia’s borders. The fundamental difference is that these coercive demands are now directed primarily at European capitals rather than Washington.
Concurrently, Russian strategists have interpreted the strategic posture of the current U.S. administration as clear evidence that the Indo-Pacific theater has permanently superseded Europe as the main arena for American global competition. Moscow’s analysts point to Washington’s reluctance to underwrite Ukraine’s war effort, its stated desire to terminate the conflict swiftly, and its ongoing diplomatic overtures to the Kremlin. The decision by Washington to grant targeted sanctions relief to Russia while applying renewed pressure on Kyiv has only amplified this assessment within the Russian capital.
Furthermore, Russian strategists assume that Washington is actively seeking to solidify its traditional dominance within the Western Hemisphere while treating China, rather than Russia, as its primary long-term adversary. In Moscow’s view, the United States is deliberately trimming its commitments in secondary theaters—principally Europe and the Middle East—to concentrate its political, military, and logistical resources on containing Beijing. While recent U.S. assertiveness in Venezuela, Cuba, and the Caribbean fits neatly into this anticipated pattern, the major military engagement in Iran has been interpreted by Moscow as an unintended deviation from Washington’s broader strategic trajectory, one that American leaders are presumably eager to correct. Whether this interpretation accurately reflects actual U.S. policy intentions is secondary to the fact that it has become the prevailing orthodoxy inside the Kremlin.
Nuclear Curiosity
Parallel to the geopolitical pivot toward Europe, Russian defense circles have grown increasingly fixated on what analysts describe as Europe’s "nuclear curiosity" and its expanding military assertiveness near Russian borders. Specifically, Moscow’s strategic planners have expressed acute concern over the ongoing modernization of British and French nuclear programs and the apparent willingness of London and Paris to wield their nuclear arsenals with greater assertiveness.
Moscow has also tracked closely the emerging prospect of French and British nuclear guarantees being extended to non-nuclear European capitals, as well as debates within non-nuclear European states regarding the potential development of sovereign nuclear options. Russian sources have frequently identified Germany, Poland, and the Nordic-Baltic nations as showing signs of this "nuclear curiosity," noting in particular public commentary by Polish officials expressing support for a national Polish nuclear deterrent.
From the perspective of the Russian General Staff, any serious initiative by a non-nuclear European state to cross the threshold into nuclear-weapon status would represent a major redline, potentially constituting a casus belli. Moreover, this growing European assertiveness on nuclear matters is unfolding simultaneously with the deployment of conventional, deep-strike precision weapons closer to Russian territory. While Western analysts view this more active European defense posture as a sensible hedge against waning American commitments, Moscow interprets it as a dangerous capability that could potentially be leveraged to execute disarming strikes against Russia’s nuclear arsenal or decapitate its political and military leadership.
To Russian observers, these trends point toward a dramatic increase in Europe’s strategic autonomy from the United States. Historically, Moscow regarded Europe primarily as a strategic logistics hub for American forces—a wealthy region of vital economic relevance but ultimately subordinate to Washington. That core assumption is now evaporating. Alongside the conviction that Europe has become Russia’s primary geopolitical adversary, the continent’s growing independence in both nuclear and conventional defense planning has emerged as a central variable in Moscow’s security calculations. Russian defense intellectuals suggest that Moscow must adapt its military posture to contain this trend, utilizing novel coercive tools to keep Europe at bay while remaining safely below the nuclear threshold.
Menacing Gestures
To operationalize this updated mental map, Russian military thinkers and defense officers have intensely scrutinized how to make Moscow’s coercive strategies more effective. During the initial years of the war in Ukraine, traditional nuclear muscle-flexing and hybrid warfare tactics proved insufficient to prevent Western allies from funneling vast quantities of financial support, advanced weaponry, and targeting intelligence to Kyiv. Nor were these measures able to deter Ukrainian land incursions into sovereign Russian territory, high-profile strikes against symbolic domestic targets, or attacks on vital Russian infrastructure, let alone compel Kyiv’s surrender.
While NATO remains deeply preoccupied with Russia’s escalating cross-domain coercion—commonly referred to in the West as hybrid warfare—Russian planners view this as only one component of a broader strategy. As Moscow recalibrates its focus toward Europe as the primary strategic threat, it is increasingly relying on a concept known as nonnuclear strategic deterrence (NNSD). For Russian military theorists, NNSD involves the systematic application of advanced conventional capabilities, including precision-guided munitions, loitering munitions, ballistic and cruise missiles, hypersonic systems, and exotic armaments such as electromagnetic-pulse and high-power microwave weapons, to deter and compel adversaries.
Conceptually, NNSD falls under what Russian experts term the "art of strategic gestures"—a euphemism for brandishing or employing both nuclear and nonnuclear capabilities to shape adversary behavior. While Russian strategists have experimented with conventional alternatives to nuclear deterrence since the early 2000s, these ideas remained largely theoretical until the outbreak of the full-scale war in Ukraine provided a real-world laboratory.
From the beginning of the conflict, Russia deployed tactical ballistic missiles, cruise missiles, and hypersonic weapons alongside massed drone attacks and maneuver warfare. Yet many Russian analysts concluded that these campaigns underdelivered when unaccompanied by overwhelming escalatory dominance. As the conflict became entrenched, Moscow increasingly turned to massive ballistic missile salvos, including the deployment of intermediate-range Oreshnik systems.
Drawing directly from these operational lessons, Russian military theoreticians now center NNSD on executing massive, deep, precision strikes against an adversary’s critical military, political, and economic infrastructure. The strategy is explicitly envisioned for application not only against Ukraine but also against its broader European backers. Although the precise parameters of NNSD are still evolving within defense literature, the concept is inherently more escalatory than the deniable asymmetric campaigns and cyber operations that have characterized Russia’s hybrid playbook in Europe.
This theoretical evolution is far from peripheral. Since 2025, the flagship journal of the Russian General Staff, Military Thought, has published numerous detailed articles on nonnuclear strategic deterrence, indicating broad traction among senior officers. Furthermore, various branches of the Russian armed forces are actively developing their own service-specific doctrines for NNSD to secure a comparative institutional advantage. This interservice competition risks normalizing increasingly aggressive forms of coercion below the nuclear threshold while heavily shaping targeting priorities and future escalation management.
The Coercion Threshold
As the Kremlin assesses the situation, the war in Ukraine was initially launched as a blunt instrument to force Europe into a fundamental overhaul of its security architecture. Yet the strategic landscape confronting Moscow today appears even more threatening than the one it sought to shatter in 2022. Washington must recognize that the Kremlin views the conflict in Ukraine not as a discrete, isolated dispute, but as a central theater in a broader, existential struggle over the future of Europe’s strategic order.
Consequently, any U.S.-led diplomatic initiative to broker an off-ramp in Ukraine must grapple directly with Moscow’s emerging castling logic and its mounting anxieties regarding European military assertiveness. A settlement that merely addresses immediate battlefield realities while leaving underlying frictions between Moscow and Europe unaddressed is likely to provide nothing more than a temporary pause in a wider, protracted conflict. Washington must understand that nonnuclear coercion has become a permanent pillar of Russia’s long-term deterrence strategy against Europe, extending far beyond the immediate context of the war in Ukraine.
Even if Moscow engages in formal negotiations to bring the conflict to a close, it is highly likely to continue employing military coercion against both Ukraine and Europe. It will do so to align the eventual terms of any settlement with its core strategic interests, to test and refine its doctrine of nonnuclear strategic deterrence, and to compel European capitals to accept a radically different continental security architecture. To achieve these ends, Russia may well deploy calibrated precision strikes against critical infrastructure, execute targeted attacks of varying intensity in Ukraine, and maintain high diplomatic pressure simultaneously.
In response, European governments—harboring deep skepticism regarding the reliability of long-term U.S. security commitments and anxious to demonstrate independent resolve—may choose to escalate their own defensive and offensive preparations. Washington must therefore brace for the possibility that intensified diplomatic efforts to end the war will coincide with a sharp increase in security risks across Europe.
Given that the current dynamic between Russia and Europe is defined by pervasive mutual suspicion, worst-case threat perceptions, and an underlying expectation of eventual direct conflict, the danger of inadvertent escalation is acute. Actions undertaken by either side for the purpose of limited coercion, signaling, or leverage risk being systematically misread, triggering a self-reinforcing action-reaction cycle where each party’s attempt to restore deterrence ironically serves to erode it further. Paradoxically, this dangerous dynamic could accelerate precisely at the moment when all key actors, including the Kremlin, are actively searching for a diplomatic off-ramp. Both Europe and Russia run the genuine risk of crossing a critical "culmination point of coercion," beyond which any additional threats or uses of force could dangerously widen the war.
For both Moscow and European capitals, the paramount challenge moving forward will be to bolster effective deterrence without crossing this perilous tipping point. For Washington, the primary responsibility lies not only in mediating the substantive terms of a peace deal, but also in mastering the delicate art of choreographing diplomacy amid ongoing military hostilities. It will be imperative for American officials to anticipate coercive moves by all participating parties without mistaking them for an outright rejection of diplomacy—and without allowing those moves to derail delicate negotiations. Ultimately, Washington will need to assist both Europe and Russia in containing their mutual reliance on coercion before a hardening security dilemma locks them into an irreversible escalatory spiral.
