The Return of Transactional Military Alliances in a Multipolar World

The ongoing transition to a more multipolar world order is reshaping how military alliances are formed and function. As power becomes more widely distributed among great and rising powers, states are reviving a traditional realist approach: alliances grounded in mutual interests, focused on specific outcomes, and characterized by strategic flexibility. This marks a departure not only from the long-term duration of post-1945 alliances, but also from their underlying assumptions—shared ideology, institutional depth, and expectations of enduring alignment. Instead, today’s alignments more closely resemble pre-WWI “marriages of convenience,” where states cooperate not because of common identity but because of converging goals in a shifting strategic landscape. In this environment, the United States must reassess its alliance strategy and adapt it to reflect the realities of interest-based, outcome-driven cooperation.

The post-WWII era was defined by two dominant alliances—NATO and the Warsaw Pact—whose members were united not only by strategic necessity but also by shared ideology and values. This fostered a rigid “us versus them” mindset, where cooperation across blocs was discouraged even in non-military domains such as trade, technology, or infrastructure. Alliances were exclusive and comprehensive, discouraging opportunistic or transactional engagement with adversaries. NATO, notably, adapted to the collapse of the Soviet Union by expanding its membership and redefining its purpose—but it remained largely anchored in value-based commitments and long-term strategic cohesion.

In contrast, today’s alliances are shifting toward a more flexible, interest-driven model, resembling the pre-WWI European balance-of-power system. States are increasingly engaging in issue-based cooperation that is pragmatic, selective, and often short-term. As the global order becomes more multipolar, these adaptable partnerships—rather than fixed ideological blocs—are likely to become the norm. According to the early classic realist theory, alliances were supposed to be like this. Hans Morgenthau in the middle of the 20th century wrote that alliances are “an inevitable function of the balance of power working within a system of more than one state and are only relevant as long as the original threat persists.” George Liska also contended that “alliances merely formalize alignments based on interests or coercion.” In simpler terms: states ally because of cold calculation of threats and opportunities, not sentimental attachment or common ideology. And when that calculation alters, so do the alliances.

According to another realist, Kenneth Waltz, bipolar systems produce more stable, enduring alliances, since under a bipolar world, the pattern is straightforward: two superstates, two blocs, and clearly defined rivalries. States know their enemies, and alignments solidify. But under a multipolar world, uncertainty is more pronounced. There are more actors, more options, rapidly changing dynamics, and greater room for miscalculation. In such a setting, coalitions are necessarily more flexible. States must continuously recompute their interests, reevaluate threats, and redefine alliances.

Unlike bipolar systems that tend toward equilibrium as each superpower checks the other, multipolar systems are marked by intense competition. States are not only reacting to immediate threats but also racing to expand their relative power—through territorial positioning, access to critical resources, development of military capabilities, and greater political influence. This race for power projection capabilities intensifies the volatility of alliances. For countries unsure whether a partner can be relied upon—or whether a rival might become useful tomorrow—short-term, interest-driven partnerships offer more strategic flexibility than long-term, ideologically grounded commitments.

In theory, every military alliance imposes constraints. Beyond requiring financial and military contributions, alliances often limit a member’s ability to pursue an independent foreign policy. For example, a state may see economic or diplomatic benefits in cooperating with an outside power, but if that power is considered a threat or rival by the alliance, pressure from allies may deter such engagement.

In a bipolar system, these constraints are more easily justified. The international landscape is sharply divided, with two dominant blocs locked in ideological and strategic rivalry. For most member states, the security benefits of belonging to a major alliance outweigh the costs of lost autonomy. The threat posed by the opposing bloc is existential and constant, leaving little room for maneuver or neutrality.

In contrast, a multipolar world presents states with a wider array of options. Threats are more diffuse, alignments less rigid, and the cost of alienating one partner can often be offset by closer ties with another. In such an environment, states are less inclined to remain in fixed, restrictive alliances. Yet no state is powerful enough to navigate the international system entirely by itself. The result is a growing preference for a middle ground: flexible, short-term, and interest-driven partnerships that allow states to hedge their bets and adapt as conditions evolve.

The return to an opportunistic, issue-based conceptualization of contemporary alliances, centered around an individual state’s broad national interests, might explain the recent criticisms regarding NATO by American and even some European officials.  With expectations of reduced American direct and indirect assistance Europeans are making preparations for a future without US support. In March, reportedly, the U.K., France, Germany, and Nordic nations were preparing a long-term substitute strategy in case America withdraws from NATO.

European states are now building bilateral and minilateral defense arrangements. In 2023, the U.K. and Turkey drew closer to defense cooperation, and a year later, France signed a defense accord with Moldova to deter potential Russian aggression. Europe is also uniting in ad hoc coalitions to provide continued support for Ukraine.

The idea of a European nuclear umbrella is gaining traction. The French President has indicated a willingness to extend France’s nuclear deterrent to other European nations—a direct response to rising doubts over the reliability of American security guarantees. In adapting to this shifting security environment, European leaders are preparing for a future in which traditional alliances lose their centrality, and cooperation is increasingly organized through pragmatic, interest-based arrangements. This evolution may not dissolve the U.S.-Europe alliance, but it is likely to reduce its ideological foundations into a more transactional, issue-based framework—one where alignment is driven less by shared identity and more by converging strategic needs.

Countries outside the West are also adopting similar strategic thinking. Russia, increasingly cut off from global markets and supply chains due to sanctions imposed by the United States, the European Union, and their allies in response to its ongoing invasion of Ukraine, has turned to China, North Korea, and Iran to meet its military and economic needs. China and Russia are now holding regular joint military exercises and have officially declared a “no-limits” relationship. Vladimir Putin and Xi Jinping signed agreements in May of 2024 to increase cooperation on space, nuclear technology, and manufacturing.

With North Korea, Russia signed a mutual defense pact late in 2024 that pledged reciprocal military aid. Russian arms and oil are being sold to Pyongyang in exchange for bullets and troops. In late 2024, under a strategic partnership treaty, North Korea deployed approximately 10,000–12,000 troops to Russia, including frontline combat units in the border-area Kursk offensive. South Korean intelligence reports later noted around 3,000 additional North Korean reinforcements in early 2025.  Russia has also been pursuing a closer relationship with Iran, transfers of critical drone components and arms sales to support its war in Ukraine. Shared resistance to the U.S.-led international allegiance has been bringing these powers together.

The behavior of certain NATO members illustrates the growing shift toward strategic autonomy and transactional diplomacy in a multipolar world. Turkey, in particular, has emerged as a “swing power” within the alliance—leveraging its geostrategic position to pursue independent policies and extract favorable concessions from both NATO and Russia. This reflects the broader realist logic driving many states to hedge and maneuver between competing powers rather than aligning firmly with one bloc.

Turkey has delivered drones to Ukraine and supported NATO initiatives in some areas, while simultaneously preserving commercial ties with Moscow, vetoing key alliance decisions, and even mediating peace talks between warring parties. Its temporary blockage of Sweden’s and Finland’s accession to NATO—until receiving political concessions—underscores its pragmatic and interest-based approach. Despite tensions, European officials still recognize that Turkey remains indispensable to regional security planning, especially amid growing uncertainty. Hungary is another case in point. Prime Minister Viktor Orbán has preserved a cooperative relationship with the Kremlin and has delayed EU and NATO measures against Russia. These actions reflect a broader trend: member states remaining within formal alliances but selectively diverging when doing so aligns with their national interests. In Hungary’s case, this includes maintaining energy ties with Russia, subtly asserting political sovereignty against Brussels, and leveraging its position within NATO and the EU to pursue domestic and geopolitical autonomy.

In the Indo-Pacific, the U.S. remains the dominant military power, but no state wants to take a formal side as regional competition with China grows. Instead, states are building networks of adaptive partnerships to hedge against China without surrendering autonomy to US national security interests. AUKUS, the Australia-U.K.-U.S. accord announced in 2021, is such a model. As an interest-based, targeted coalition, it was established to share defense technology, including nuclear-powered subs, and resist China’s increasing maritime presence. Even Japan, a contemporary US ally with a shared perception of China as a threat, is now adjusting its regional role to be more cooperative with China, pursuing more pragmatic economic engagement and dialogue with Beijing while continuing to bolster its defense capabilities.

Similarly, India conducts joint military exercises with the U.S., hosts American aircraft, and collaborates on jet engine and drone technology. Yet New Delhi still buys weapons from Russia and remains outside any mutual defense treaty. Its strategy is based on autonomy and strategic hedging at the same time, believing it can more effectively pursue and achieve its national interests by pursuing temporary, issue-based agreements.

The Southeast Asia region also demonstrates this balancing act. The Philippines has enhanced defense ties with the U.S. and Japan, with new base access and collective maritime patrols. Nevertheless, Manila engages in trade with Beijing. Vietnam, Malaysia, and Indonesia also court China and the West, embracing flexible partnerships that make space for maneuver.

These actions, while introducing a degree of uncertainty regarding the future of international order and maintenance of global stability, are entirely natural according to the traditional realist perspective. Realist scholars have warned that once the original threat maintaining an alliance dwindles or is perceived weaker, and thus no longer requiring a dedicated security alliance to counter, interest in maintaining close coordination declines as well. Under a multipolar world, where threats are no longer one-dimensional and power is dispersed among multiple poles, flexibility is logical. Turkey, Hungary, and others are simply behaving as rational agents of national interest, responding to changing geopolitical conditions. Therefore, this move back towards transactional, realist-style coalitions is not an abnormality but a product of multipolarity. The Cold War permanent military blocs model is being supplanted by a more differentiated but resilient order. In such an atmosphere, the United States must learn to adapt, not resist.

First, Washington will need to reshape its approach to alliance-building by prioritizing flexible bilateral and minilateral coalitions. Rather than expecting allies to commit to broad, long-term partnerships, the United States will need to focus on forming coalitions centered around specific strategic objectives such as deterring China’s maritime assertiveness in the Pacific, sustaining military assistance to Ukraine, or safeguarding critical global supply chains.

While Cold War-era alliances like NATO were also rooted in strategic interests, they were reinforced by shared ideology, deep institutional ties, and an expectation of enduring alignment. Even after the collapse of the Soviet Union, these alliances persisted, often expanding rather than dissolving. In contrast, today’s multipolar environment lacks that ideological cohesion. States are navigating a more fluid landscape in which cooperation is often limited to narrow areas of convergence, and alignment does not imply broader loyalty. In this context, U.S. leadership will depend less on permanent structures and more on its ability to build adaptable, outcome-oriented coalitions that reflect partners’ evolving priorities.

Second, the United States will need to reinforce its credibility as a dependable security partner and regional stabilizer, regardless of the scale or form of a given alliance. In an era defined by adaptive coalitions and strategic flexibility, dependability remains a central pillar of effective statecraft. This includes honoring agreed commitments, consulting closely with partners on shared challenges, maintaining clear communication, and minimizing abrupt or uncoordinated policy shifts.

In a multipolar environment where more actors have the capacity to shape regional outcomes, credibility serves as a key force multiplier. Maintaining trust and alignment with partners ensures that American leadership remains central in shaping global norms, coordinating collective responses, and securing long-term strategic interests. The objective is not to preserve alliances for their symbolic value, but to sustain meaningful cooperation through predictable, mutually beneficial engagement. In a world defined by anarchy, predictability stems from states clearly articulating shared interests and establishing incentives for mutual gain. The traditional realist renaissance of objective-based, rather than identity-based, alliances is already in full swing. For states, this shift holds as much potential as risk. The challenge for the policymakers is to make sure they grasp the current trend correctly, calibrate their expectations from other states accordingly, and taking the appropriate steps to maintain an alignment of interests with others in an evolving world.

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