Smaller states are the neglected stepchildren of the nuclear age. Described as “paranoids, pygmies and pariahs,” and paternalistically characterized as “protégés” within alliances, the literature has little to say about the nuclear choices of smaller states (Betts, 1977; Betts, 1993). This is the great paradox of the third nuclear age, which is partly defined by smaller states and their choices, leading to increasing heterogeneity, realignments, and competition that together challenge longstanding assumptions about deterrence and escalation risks (Narang & Sagan, 2023). While scholars increasingly acknowledge this role of small states in the third nuclear age, they have stopped short of analysing the behaviour of these states in this moment, or how they are shaping it. That is where this article, and the special collection it introduces, begins.
In this introductory article to the special collection on NATO, small states and the third nuclear age, we examine small states as participants in extended nuclear deterrence. The case universe consists of relatively smaller states – states with limited capability to influence international relations (Keohane 1969), populations less than 10 million and limited geographic depth – participating in extended deterrence arrangements. Compared to medium-sized or large nuclear powers that either use nuclear weapons to ensure their own survival or extend their protection to others, much less is known about how these small non-nuclear weapons states participate in contemporary extended deterrence arrangements.
While scholars have emphasized different drivers and characteristics of this third nuclear age, the changing participation and capabilities of smaller states in evolving extended deterrence relationships remains underexplored. This participation not only reflects the changing political and technological characteristics of this new nuclear age; it unlocks the most transformative aspects of this new nuclear age in terms of the impact of smaller states on deterrence logics and formats.
Hence, we focus on the key strategic features of this category of small non-nuclear states and their evolving participation in deterrence in the third nuclear age. By doing so, this article adds to extant discussions of the security strategies of small and medium powers (Pedersen, 2023; Keohane, 1969; Wivel et al., 2014; Bailes et al., 2014; Nagy, 2022; Edström and Westberg, 2020; Goh, 2008).
We develop the first analytic framework specifying the key features of small states in extended deterrence relationships, as defined by their bargaining power vis-à-vis nuclear hegemons, geography, and the development of conventional arsenals that can create strategic effects. We also outline the adaptive political and military strategies that these smaller states draw on to address the resulting weaknesses in their postures at a moment when the main nuclear patron, the United States, is becoming less reliable. Through these strategies, we argue that smaller states fulfil new roles in extended nuclear deterrence formats in ways that are distinct from previous decades.
Although many of these changes are enabled by technological developments, their main engine is political, driven by the erosion of U.S. extended deterrence, which has served to contain the capabilities and ambitions of smaller states during the first two long nuclear ages. The transforming threat environment in Europe and Asia demands a rethinking of the political and military infrastructure of extended deterrence arrangements, while technological advances challenge longstanding assumptions about the escalatory drivers and options that are available to smaller states versus larger nuclear powers. The announcement in March 2026 of the French concept of “forward deterrence” raises additional questions about the future formats of deterrence in Europe, which are likely to look different from the approach developed by the United States during the Cold War but are set to build on “shouldering” –combining conventional and nuclear assets targeting an expansive set of escalation risks. Norway and France announced the Narvik mutual defence agreement in May 2026; Sweden and Denmark were among the first group of states mentioned by Macron in making this announcement.
Taken together, we argue that this transformation of the intentions and capabilities of these actors has profound implications for extended deterrence arrangements. These developments have outsized effects on U.S. allies in Europe and Asia, whose nuclear choices have been contingent on U.S. extended deterrence. Several states are now openly reassessing their nuclear choices in an unprecedented fashion.
This article also fills several longstanding gaps in the nuclear literature. While the literature on nuclear states offers rich insights into individual cases, it lacks systematic frameworks to understand the orientation of smaller states in nuclear contexts – the third nuclear age, particularly. Further, it is unable to explain the emergence of compensatory strategies that enable some of these smaller states to escape or work around their relative weaknesses. Our arguments address calls for updated analyses of nuclear strategy and deterrence that more closely reflect the key actors and threat environments than the outdated and, in key cases, contested theories of nuclear strategy and statecraft from the Cold War era (Narang & Vaddi, 2025; Panda, 2025; Lieber & Press, 2016; Bell, 2015).
We develop these arguments in three sections. First, we define and discuss the key features of the third nuclear age and their implications for smaller states, highlighting two trends that reshape the role and prospects of smaller states in the third nuclear age. Second, we develop a case universe describing the varied positions and roles of non-nuclear allied states in extended deterrence arrangements. Third, we describe four different external and internal balancing strategies that are now open to these states. They reflect how current developments in alliance bargaining, technology and strategy enable smaller states to band together, enabling them to play an increasingly independent and supplementary set of roles in extended deterrence arrangements (Narang & Vaddi, 2025). We conclude by highlighting vital new insights for policy and analysis from the contributions to this special issue and present new research avenues for analysing key shifts and transformations of the third nuclear age.
Smaller States Confront the Third Nuclear Age
The three nuclear ages are defined by the imprint of different kinds of states on nuclear strategy. Whereas the first nuclear age (1945–1991) was created in the image of the two superpowers, the United States and the Soviet Union, the second nuclear age (1991–2019) was defined by the emergence of new nuclear powers whose postures were shaped by different constraints and perceptions of deterrence than those of the Cold War superpowers (Narang, 2014). The third nuclear age (2019–) is identified by a larger and more heterogeneous group, comprising a range of nuclear powers as well as states participating in extended deterrence arrangements (Naylor, 2019). Hence, the strategies and adaptive steps of smaller states or “protégés” in terms of their allied postures and capabilities are set to play an important role in the new global nuclear order as well as the nature of extended deterrence. In the following, we provide an overview of these shifts to set the baseline for these adaptive shifts and their implications in the following sections.
During the first nuclear age, the United States and the Soviet Union extended nuclear umbrellas to curb proliferation among allies and satellite states. As more regional nuclear powers such as France and the United Kingdom emerged, their distinctive needs and constraints led to different nuclear postures, with some pursuing close integration with the U.S. (the United Kingdom) and others taking steps toward greater independence (France). For the two nuclear superpowers, the balance of terror remained a delicate exercise, whereas regional nuclear powers did not pursue damage limitation options at the same level and scale as the superpowers, given their distinct roles and deterrence needs.
With the implementation of Flexible Response in NATO in the late 1960s, escalation risks in Europe became a defining challenge with particular implications for regional powers and frontline states. Avoiding entanglement in destabilizing allied arrangements became a core strategic issue for frontline states such as Norway (Tamnes, 1986). At the political level, the abandonment versus entanglement (Kim, 2011) challenge facing smaller states became pressing with varying U.S. political commitments to allied states.
The collapse of the Soviet Union and the emergence of new nuclear weapons states, including Pakistan and North Korea, led to the advent of the second nuclear age. Nuclear dynamics were dominated by Cold War concerns (Turnbull III, 2015). The reorientation of NATO toward out-of-area operations and the impact of the peace dividend on many other U.S. alliances in the post-Cold War era led to a massive reduction of U.S. nuclear arsenals and deployments in Asia and Europe. At the same time, the regional nuclear powers presented a much more complex picture. During the 1990s, some regional nuclear powers such as the UK and France reduced their nuclear platforms (e.g., airborne) and types of nuclear weapons, South Africa opted to destroy its nuclear weapons alongside the end of the apartheid regime (Moser, 2024), and India and Pakistan conducted nuclear tests in May 1998. As nuclear proliferation emerged as a defining challenge of this nuclear age, the nuclear advances in states such as North Korea and Iran were curtailed, while those of other states, such as Iraq and Libya, were thwarted.
The end of the second nuclear age was characterized by overdue modernization of the U.S. nuclear arsenal, paired with growing enthusiasm for missile defences. The dominance this signalled on the part of the United States triggered reactions from Russia and China, who made moves to challenge advances in the superpower’s capabilities and influence. But at the same time, the policies of the first Trump administration (2017–2021) instilled doubts about the credibility of U.S. extended deterrence. Thus, the underlying strategic dynamics of the third nuclear age are defined by renewed great power competition, intensifying proliferation risks, emerging arms races and the potential for non-nuclear armed states to influence strategic dynamics through the possession of what Futter and Zala (2021) describe as strategic non-nuclear weaponry (Miller & Narang, 2018; Narang and Sagan, 2023).
While many of these elements are not new as such, the changing role and influence of smaller nuclear powers and allies together generates a broader shift in the workings of extended deterrence. In this new era, extended nuclear deterrence arrangements include more heterogeneous actors, including those armed exclusively with conventional capabilities, who play an increasingly varied set of roles and pursue an expansive set of options and formats for participation. Some of these actors assume attributes and behaviours that used to be the reserve of nuclear hegemons and form new deterrence clusters that cut across longstanding divisions of conventional and nuclear capabilities and activities. This shift stands in contrast to the dearth of theorisation with regard to nuclear strategy and small states and reflects similar patterns in the small state literature focusing on security and defence.
The main driver of the transformation of the role of smaller nuclear powers is the erosion of allied confidence in U.S. extended deterrence, both in Europe and Asia. This disrupts the social contract that held across the first two nuclear ages, in which smaller states either abstained from or abandoned nuclear weapons programmes, or significantly constrained their own nuclear capabilities, in return for protection and participation under the U.S. nuclear umbrella. Before Russia’s full-scale invasion of Ukraine in 2022 and the arrival of the second Trump administration, there were warnings that these developments could upend the slowing pace of proliferation and introduce new nuclear weapons states, as “other potential nuclear weapons states lurk in the wings – U.S. adversaries and allies alike – such as Saudi Arabia, Turkey, and perhaps South Korea, Japan, and Germany who may not indefinitely find America’s extended deterrence commitments credible” (Narang & Sagan, 2023, p. 2).
The disruptions following the Russian full-scale war of aggression on Ukraine and Trump’s second term have already led several smaller states in Europe and Asia to rethink their past decisions to abstain from nuclear weapons, while nuclear weapons states in Europe have been encouraged to expand their arsenals and postures, including their participation in extended deterrence arrangements (Freedman, 2025; Bell & Hoffman, 2025). These emerging developments outpace the existing theoretical frameworks: conceptual and theoretical foundations for assessing how smaller nuclear states seek to address their specific limitations remain particularly thin.
The second driver is technological shifts transforming the escalatory options for smaller states, acting either independently or in conjunction with nuclear powers. The changing security environment has led smaller nuclear weapons states to expand the robustness and capabilities of their nuclear arsenals in response to expansive threats and the capabilities of nuclear adversaries such as Russia and China. In Europe, the realization that the United States cannot be fully relied upon in a nuclear crisis has led states to expand their own arsenals in qualitative and quantitative terms (Brustlein, 2018; Brustlein, 2017). Smaller nuclear-armed states are developing advanced offensive capabilities and banding together with other states in new configurations that directly threaten the nuclear superpowers, notably the United States.
As smaller states develop more robust conventional and situational awareness capabilities to either reduce reliance on the United States or, as Withorne suggests in this special collection, to gain leverage with the United States, these expanded capabilities and roles introduce new risks (Withorne, 2026; Ven Bruusgaard, 2024). Such risks are intensified by compressed decision-making timelines and opaque signalling environments, which disproportionately affect smaller states with limited early-warning infrastructure or complex alliance dependencies. As Narang and Sagan (2023) note, newer or smaller nuclear powers (especially those facing internal instability) are under pressure to adopt operational practices such as early delegation of launch authority, forward deployment of nuclear assets, or peacetime movement of warheads. These behaviours, intended to preserve survivability, can increase the risk of accidental or unauthorized use. Moreover, even in cases where technical survivability is achievable, the perception of vulnerability in asymmetric rivalries can heighten escalatory pressures. Emerging digital platforms and rapid information flows complicate de-escalation efforts, particularly for states lacking robust crisis communication tools (Williams & Drew, 2020).
Taken together, technological convergence, digital entanglement, and doctrinal ambiguity in the third nuclear age pose distinct and often disproportionate challenges to small and medium states. How these states respond to these challenges remains an undertheorized and empirically underexplored question.
Finally, escalation options and risks in the third nuclear age are increasingly complex. As Futter and Zala (2021) note, digital convergence and the co-mingling of nuclear and non-nuclear systems heighten ambiguity during crises for states with less resilient second-strike postures. High-precision long-range conventional weapons, cyber capabilities, and intelligence, surveillance and reconnaissance (ISR) architectures blur the nuclear–conventional threshold, and heighten the risks of misattribution, entanglement, and inadvertent escalation could increase in strategic hotspots, including the High North.
The existing literature highlights escalation risks as especially pervasive and dangerous for smaller frontline states. Barry Posen’s (1991) classic analysis of NATO’s northern flank emphasized how tightly coupled conventional and nuclear operations created structural risks of inadvertent escalation for forward-deployed allies. Pre-delegated nuclear authority, rapid reinforcement timelines, and doctrinal ambiguity increased the likelihood that a local conventional conflict could trigger nuclear use before escalation could be politically managed through vaguely defined consultation mechanisms with U.S. allies. Northern flank frontline states, notably Norway, faced significant strategic exposure due to their proximity to Soviet forces and their integration in NATO’s early-warning architecture. To manage these risks, Norwegian authorities developed screening mechanisms to reduce unintended escalation risks associated with their integration into allied defence; over time, however, integration tended to override screening restraints (Tamnes, 1986; Hilde, 2019). As Erästö and Wan highlight in this special collection, the third nuclear age heightens these risks as technology converges with the expanded NATO alliance and the reality of undermined and weakened screening mechanisms (Erästö and Wan, 2026).
Categorizing Smaller States in the Third Nuclear Age
The diversity in terms of geography, economic and military resources, and threat perceptions of smaller states complicate efforts to predict or systematically assess both their position and influence in extended deterrence arrangements. States tend to form stable preferences about their level of participation, as Herzog and colleagues show (Herzog, Rodriguez & Sukin, 2026). However, geopolitical turbulence can upend these preferences, as seen in the Nordic countries since 2022 (Braut-Hegghammer & Hagstrom, 2026) and in the case of South Korea (Kim, 2025). Allies such as Poland, who have expressed a desire to enhance their participation and move towards nuclear sharing, have been rebuffed by the patron or other allies.
Below, we examine three distinct sets of constraints that shape the options and choices for smaller states with regard to extended nuclear deterrence.
The first constraint is the periphery problem. Smaller states do not enjoy equal bargaining power in extended nuclear deterrence due to their distinct assets and the asymmetric political power of nuclear hegemons. Some may be frontline states with key assets for the nuclear patron; their exposed situation also makes them vulnerable to the changing priorities and strategic needs of the hegemon. Others, such as Iceland, may have limited military assets to offer, making them highly reliant on their protectors. This reflects the core challenge for extended deterrence: securing the patron’s commitment and navigating the potential risks this entails in terms of escalation. In the literature on small states, this has been framed as the abandonment/entanglement problem, which closely mirrors how smaller states have been described as navigating their dependence on their stronger ally. This reduces their freedom of political and strategic manoeuvre and often leaves them vulnerable to changes in the nuclear hegemon’s postures.
The second constraint reflects the competing demands for limited resources in smaller states. Building and maintaining nuclear weapons requires highly specialized industrial capabilities and access to material such as enriched uranium. No small state has developed nuclear weapons without some form of external assistance. Smaller states lack the material capacity to independently develop and maintain sufficient strategic capabilities equal to those of their larger adversaries. In other words, the costs of acquiring such capabilities are high and require substantial continued investment as platforms age and adversaries innovate (Narang, 2022). Upgrading a nuclear arsenal is both expensive and technically difficult, and the long timelines suggest that modernization programmes are built on outdated threat perceptions, leading to inadequate replacement capabilities. The cost of deploying, maintaining and modernizing nuclear capabilities must be considered in relation to the need to sustain conventional forces. Few countries have the resources to maintain modern nuclear and conventional forces; for example, if one removes the nuclear component of the UK defence enterprise, Britain spends 1.9% of GDP on its defence, a sum now below the majority of non-nuclear NATO countries (Boileau & Warner, 2025).
The third constraint relates to the geographic features of smaller states. Many smaller states are faced with a lack of strategic depth due to their geographic features, which increases their vulnerability and restricts their strategic options. The primary sources of this vulnerability are an inability to absorb punishment and an inability to protect strategic assets. This can lead to distinct escalation risks and pathways, such as use-or-lose incentives, that are not aligned with postures taking mutually assured destruction as their point of departure. Japan and South Korea, to name two examples, are militarily powerful states that face significant challenges in terms of their military geography. Nordic states face similar problems: despite large land masses, populations and critical government functions are concentrated in a small number of areas, making the implementation of deterrence a complex endeavour.
Set against this background of enduring constraints, the compensating strategies we explore in the following section highlight the expansive set of options for smaller states seeking to change or expand their contributions as patrons or protégés within extended deterrence.
Adaptive Strategies for Small States
The core constraints faced by the three categories of states have posed enduring challenges throughout the first and second nuclear ages. In the third nuclear age, smaller states can draw on four adaptive strategies to potentially overcome these challenges.1 In adopting one or more of these strategies, smaller states may not only increase their leverage within extended nuclear deterrence relationships but also acquire new roles within them. Further, conventionally armed states that currently enjoy the protection of extended deterrence could, arguably for the first time since the advent of nuclear weapons, play an important role in shaping the strategic threat environment to their benefit, by developing indigenous and collective conventional capabilities.
The first grouping of adaptive strategies involves three variations of external balancing (Walt, 1987). First, smaller states can build closer nuclear-operational links with their nuclear hegemon. These arrangements first appeared during the Cold War with the advent of nuclear sharing, where both regional nuclear powers and smaller non-nuclear states used their own aircraft to carry U.S.-controlled nuclear weapons. Such nuclear sharing agreements serve a number of purposes within the alliance and as a deterrent. These include enhancing deterrence signalling by demonstrating the commitment of the nuclear patron to protect its smaller allies, providing smaller states with a role in their own nuclear security while consequently locking nuclear weapons into alliance commitments and using nuclear sharing arrangements to offset other deficiencies in conventional posture and alliance spending commitments (Desmaele, 2025, p. 3).
Currently, five non-U.S. NATO members, including Germany, host U.S. tactical nuclear weapons and possess the dual capable aircraft (DCA) capabilities which could deploy nuclear weapons (Von Hlatky & Lambert-Deslande, 2024, p. 509). While there is some scepticism over the continued deterrent value of such arrangements, they are still valued by both embedded states and their patrons. In 2025, the United Kingdom announced that it would restart nuclear sharing arrangements with the United States by purchasing nuclear-capable F-35A aircraft (Prime Minister’s Office, 2025a). For states that do not participate in nuclear sharing, there are other options to support the nuclear hegemon. These include participating in consultative arrangements such as NATO’s Nuclear Planning Group or deploying conventional forces to support nuclear deterrence operations. In NATO, the latter option is formulated through the Conventional Support for Nuclear Operations (CSNO) concept. In NATO’s 2025 Steadfast Noon nuclear exercises, 70 DCA and conventional-only aircraft from 14 countries practised alliance nuclear operations.
Second, small states could participate in either smaller ad-hoc or more formal deterrence clusters with regional nuclear powers to offset their vulnerability to abandonment risks posed by the nuclear hegemon. This requires the regional nuclear power to accept the responsibility of extended deterrence. Recent events in Europe have led to efforts by both nuclear and non-nuclear states to build such groupings. Discussions and now agreements surrounding closer alignment between the two European nuclear powers – France and the United Kingdom – provide the clearest example of this. The July 2025 Northwood declaration states that French and British “nuclear forces are independent but can be coordinated” (Prime Minister’s Office, 2025b).
The March 2026 announcement by President Macron that France would expand its nuclear arsenal and introduce a new concept called forward deterrence, thereby extending what Paris would consider its vital interests beyond the borders of France, marks another step in this development (Fayet, 2026). On the same day, Germany and France announced the creation of a nuclear steering group (German Federal Government, 2026) and Paris pledged to deepen coordination with a number of other smaller non-nuclear European countries, including Sweden and Denmark (Fayet, 2026). These kinds of agreements are likely aimed at mitigating potential U.S. abandonment while simultaneously reinforcing European deterrence postures and signalling vis-à-vis Russia.
As multiple studies have pointed out, even in such a regional setting, issues of credibility remain, and transitioning from nuclear postures ostensibly designed for national deterrence to something that covers other functions alongside other partners requires political investment, alterations in NC3, and likely increases in nuclear arsenal size. Indeed, questions about the ability of regional nuclear states to independently extend deterrence over other states tend to centre on arsenal limitations. Further, nuclear asymmetries in relation to the primary adversary, Russia, particularly in terms of tactical nuclear weapons, speak to the need for nuclear clusters to ensure that their arsenals are adjusted in relation to the new roles that they take on. But, as President Macron stated, France, with its independent nuclear infrastructure, may be willing to pursue such an approach in collaboration with European partners.
For these regional nuclear powers, the option to pursue either counterforce (a strategy designed to destroy or deplete the nuclear forces of an opponent, see Long & Rittenhouse Green, 2015) or damage limitation (a broader approach to limit the effectiveness of an opponent’s nuclear attack of which counterforce is one component, see Stewart, 1967) must be weighed against the decision to extend deterrence to other allied states and size of their arsenal. However, the emergence of advanced targeting and high precision systems means that some regional nuclear powers can now efficiently pursue a diversified nuclear posture which, while not explicitly counterforce, could include targeting military, economic and political centres of power to impose “intolerable” costs to an aggressor such as Russia.
A third, more novel, balancing option is the creation of conventionally armed regional clusters, which can leverage their collective military potential to enhance nuclear influence with their patron and shape the strategic calculations of their primary adversary. Such clusters can take many forms – bilateral or multilateral cooperation within an alliance, as in the Nordic region, or through ad hoc agreements. Investment in capabilities including long-range precision strike, ISR, command and control (C2), cyber weapons, and space-based systems gives these states the ability to threaten the key strategic infrastructure of nuclear states and even nuclear hegemons. While most small states individually lack the resources to generate sufficient mass to influence deterrent or escalation dynamics in an adversarial relationship with a hegemon, clustering with geostrategically proximate states of similar capability mitigates some of this weakness. Such clusters may also be able to provide enhanced conventional support to their allied hegemon’s nuclear operations, while giving member states greater bargaining power – both by creating new avenues of strategic opportunity and by imposing higher costs of abandonment.
The fourth option for small states is to balance internally by developing capabilities with strategic relevance. Smaller states can now operationalize long-range precision strike architectures, deploying conventional capabilities – precision strike, missile defence, and cyber weapons – with strategic effects. South Korea is a rare example of a state that overtly pursues a conventional counterforce posture through the development of large numbers of offensive and defensive weapons (Bowers & Hiim, 2021). A growing number of European states, including the Nordic countries, are investing in long-range precision strike capabilities that could influence adversary perceptions of strategic stability. Norway’s introduction of the F-35, Joint Strike Missile, and Chunmoo MLRS now gives Oslo the theoretical ability to strike vital Russian nuclear infrastructure on the Kola Peninsula. While such a scenario remains unlikely, and any conventionally armed state must contend with a nuclear adversary’s escalation dominance, the possibility of strategic assets being destroyed by conventional weapons is one that Russian defence planners cannot ignore.
Vitally, as highlighted above, the benefits of such internal balancing extend beyond national defence to enhance the small state’s options and leverage in both formal and ad hoc extended deterrence arrangements. The possession of such capabilities provides small states with the ability to contribute in new ways to nuclear deterrence; they can now go beyond supporting the deployment of the hegemon’s nuclear weapons by actively engaging in integrated conventional-nuclear warfighting through the conventional targeting of strategic assets.
The Nordics, NATO and the Third Nuclear Age
The Nordic countries of Norway, Finland, Denmark and Sweden capture many of the conditions of the third nuclear age described in this introductory article. All are smaller states possessing advanced conventional military capabilities and are members of NATO; all share land or maritime borders or boundaries with Russia; all consider the Arctic, the Kola Peninsula and the Baltic Sea as their area of operations. Moreover, through mechanisms such as Nordic Defence Cooperation (NORDEFCO), they have the capability to combine into a cluster to increase their influence, not only within NATO, but also with regard to the United States – the sole provider of extended deterrence for all three nations.
As the articles in this special issue demonstrate, these Nordic countries now have the potential, if not necessarily the intention, to influence both strategic stability and deterrence calculations in both a Nordic context and in the wider NATO-Russia dynamic. Further, all four now show an awareness of the constraints the smaller state faces in the third nuclear age; and, importantly, they are beginning to mitigate them through variations and combinations of the adaptive strategies discussed above.
Målfrid Braut-Hegghammer and Lauren E. Hagstrom trace the evolution of the Nordic countries from ostensibly dovish origins towards more hawkish allied postures, and analyses the role of domestic drivers in shaping such change. Through the strategy of clustering, the three Nordic countries have been able to overcome specific, but longstanding, constraints in terms of alliance posture, strategic depth and extended deterrence. Their findings add new insights to debates on domestic drivers of nuclear choices, allied posture transformation, and the nuclear choices of protégés using the Nordic allied postures in the High North as a case study (Braut-Hegghammer & Hagstrom, 2026).
Delving further into the concept of clustering, Matti Pesu examines how Norway, Sweden and Finland have become key to NATO’s Arctic posture. He argues that the emergent Nordic deterrence cluster has both internal and external roles. From an external perspective, the collective deterrent capacity of the three Nordic countries creates a strong deterrent signal for Russia. Internally, the cluster serves to influence NATO decision-making and strategy in relation to the Arctic and High North. However, Pesu caveats these findings by highlighting the need to maintain and further develop cohesion and synchronization within the cluster, given Russia’s emphasis on creating and exploiting allied cleavages (Pesu, 2026).
Examining how allies seek to manage their relative security postures within alliances is a crucial question explored in the article by Stephen Herzog, J. Luis Rodriguez and Lauren Sukin. They argue that states broadly shape their preferred posture based on their vulnerability to nuclear-armed adversaries and their own relative military strength. Their article develops a typology of four types within NATO: frontliners, hedgers, influencers and subordinates, demonstrating the equivocal nature of alignment between the allies regarding the challenges to the credibility of U.S. extended deterrence. The analysis includes findings from a survey of 10 NATO member states, drawing out implications for policy and analysis of the varied impact of future changes in U.S. allied commitments (Herzog, Rodriguez & Sukin, 2026).
Fabian Hoffman’s article examines the operational and strategic implications of Finland, Sweden and Norway’s procurement and deployment of conventional long-range precision strike weapons. Hoffman first develops a novel framework for understanding the tactical, operational and strategic roles such weapons play on the battlefield. He demonstrates that such weapons have the potential to strike strategic nuclear sites, including launch platforms, storage facilities and C2 nodes. Nordic countries are, however, doctrinally wedded to the use of such capabilities for conventional war fighting, and they are unlikely to have sufficient mass or the political will to target sites with such strategic implications. Notwithstanding these operational realities, Russian perceptions of the potential impact of such weapons will likely ensure negative consequences for strategic stability in the region – demonstrating the the strategic influence of smaller states (Hoffmann, 2026).
Jamie Withorne’s paper delves further into the capacity of small states to contribute to alliance objectives and thereby gain leverage within said alliance. Using Norway as a case study, Withorne examines the role of situational awareness (SA) as a tool for small states to provide value-added capabilities to an alliance. To do so, the paper uses an analytical framework to capture the key components of SA, demonstrating that while technology has improved observation capacity, understanding the data retrieved remains a uniquely human endeavour not yet soluble by technology. Nevertheless, under the given conditions of deterrence complexity and ever-present conventional and nuclear escalation risks, small states such as Norway can leverage situational awareness capabilities to overcome the periphery problem, navigate escalation pathways and become key contributors to an alliance or hegemon’s strategic posture (Withorne, 2026).
The perspective of the United States and its management of politically constrained but strategically vital allies is explored in a paper by Hasini Ransala Liyanage. Using the U.S. management of allies Norway and Denmark from the Cold War to the present day, Liyanage argues that the United States showed a high degree of flexibility when dealing with both Oslo and Copenhagen. The article demonstrates that, while the United States at times preferred hardware commitments to support its nuclear posture, it was willing to accept software commitments such as ISR, logistics and exercises from allies with reluctant or non-cooperative publics. Liyanage highlights how this approach has relevance for today as the Nordic states and the United States adjust their military and strategic postures in reaction to the shaping factors captured by the third nuclear age (Liyanage, 2026).
The emergence of the Nordic deterrence cluster reflects a broader trend across Europe and NATO regarding the need to toughen its military posture and increase procurement following Russia’s full-scale invasion of Ukraine. However, as Wilfred Wan and Tytti Erästö argue, the adoption of such measures, no matter how necessary, has not been matched by efforts to ensure that conventional and nuclear escalation risks are being managed. In their foundational article, they explore the potential sources of escalation emerging from the new security dynamics in the High North and the Baltic region and their potential impact on nuclear crisis stability. Further, they demonstrate how existing structures, strategies and agreements aimed at mitigating such risks have eroded, thereby increasing the potential for escalation. The authors conclude with recommendations for future risk reduction; in doing so, they acknowledge the political difficulties of such initiatives by emphasizing the need for longer-term strategic thinking surrounding this issue (Erästö & Wan, 2026).
The final paper in this special issue provides a contrasting case study, examining the rationale behind the 2022 Russia-Belarus nuclear agreement, which ostensibly mirrors NATO nuclear sharing arrangements. Using a congruence analysis of official statements to compensate for the lack of high-quality data, Alexander Sorg and Liviu Horovitz find that traditional understandings of extended deterrence offer the most powerful explanation for the agreement. As this case suggests, non-Western protégés and smaller powers may face different pressures from their patrons than Cold War arrangements would imply – pressures that echo those arrangements in some respects and surpass them in others (Sorg & Horovitz, 2026).
Notes
Acknowledgements
We gratefully acknowledge support for this special issue from the small grant scheme from the Department of Political Science, University of Oslo. For excellent discussant comments and suggestions in the two author workshops we thank the participants, and especially Scott Gates, Henrik Hiim, Do Young Lee, and Andreas Østhagen. We are grateful to the anonymous reviewers for their helpful suggestions and feedback.