The Collective Security Treaty Organization (CSTO), formally established in 2002, was initially designed to counterweight NATO in the post-Soviet space. Emerging from the geopolitical vacuum left by the collapse of the Soviet Union, the CSTO aimed to ensure Russian dominance in Central Asia and the Caucasus by providing a multilateral security framework under Moscow’s leadership. Beyond offering a collective military shield, it was meant to institutionalize Russia’s influence over the former Soviet republics and reinforce a regional order centered on Kremlin priorities. The alliance, comprising Armenia, Belarus, Kazakhstan, Kyrgyzstan, Russia, and Tajikistan- became a founding pillar of Moscow’s post-Soviet geopolitical strategy. It allowed Russia to project its centuries-old ambitions in its so-called "near abroad”, deter Western encroachment, and legitimize military interventions under the banner of mutual defense.

For years, the model held and was considered mutually convenient for both the Kremlin and the smaller members. However, in recent times, and because of the latest event, particularly with the outbreak of the war in Ukraine in 2022, the CSTO has shown signs of severe strain. The Organization is now surprisingly marked by growing internal tensions, diverging national interests, and a creeping loss of credibility. The Ukraine war has not only exposed the limits of Russian military power, but the unexpected indifference of some members in backing Russia has also accelerated centrifugal forces within the CSTO. Armenia, for example, has openly questioned the alliance’s utility; Kazakhstan, due to the emergence of other regional actors, has pursued a more autonomous foreign policy; and even traditionally loyal partners like Belarus find themselves navigating shifting alliances.

The alternative centers of influence, namely China and Turkey, are gaining ground. Beijing has deepened its economic and security footprints in Central Asia and beyond thanks to the “Belt and Road” initiative. Ankara, on its side, leveraging linguistic, cultural, and religious ties, is carving out an increasing role in the South Caucasus. In this power vacuum even NATO and the West, though not directly engaged, are beginning to reconsider their role on the edge of Russia’s sphere of influence. As the CSTO falters, the post-Soviet space is no longer anchored in a single center of gravity, but increasingly caught in a quiet, accelerating struggle for alignment, autonomy, and survival.

Ukraine and the shattered illusion of Russian security

When Russian troops crossed into Ukraine in February 2022, the Kremlin envisioned a swift operation, a demonstration of power meant to reassert control over the Donbas and Lugansk contested region, Kyiv, and, by extension, to reduce centrifugal forces and influences across the post-Soviet space. Instead, the war turned into a prolonged and brutal conflict revealing profound structural weaknesses in Russia’s military apparatus, and in the system of alliances long taken for granted by Moscow’s elites. For years, CSTO member states operated under the strategic assumption that Russian hard power was effective and enduring. That assumption was quickly questioned in Ukraine, where Moscow's failure to achieve rapid victory revealed an overreliance on third parties like Iran.

Moreover, Russia’s preoccupation with the Ukrainian front has diminished its capacity to project forces and influence elsewhere. The CSTO, never known for its robust institutional autonomy, is reliant on Russian leadership, logistics, and financing, with an imbalance of power between Russia and the other members. With Moscow consumed by a costly war, the alliance's operational credibility has waned. The other member states are not blind to this and the CSTO's inability to enforce cohesion during a period of escalating global tension has only intensified doubts about its sustainable endurance.

The symbolic collapse is perhaps even more telling than the material one. Russia, once perceived as the ultimate arbiter of stability in Eurasia, has now become a source of instability. The war exposed a deeper paradox at the heart of the CSTO: the tension between sovereignty and loyalty. Many member states have built their post-independence identities on careful balancing acts — affirming their sovereignty while maintaining strategic ties to Moscow.

Russia’s invasion of Ukraine conveyed a stark message to its neighbors: that former Soviet republics seeking to assert a more autonomous, Western-oriented foreign policy risk provoking coercive responses, including the use of force. Rather than reinforcing cohesion within the CSTO, the war has deepened underlying mistrust and accelerated a process of psychological disengagement. Across member states, particularly among younger political elites, there is a growing recalibration of foreign policy priorities — one increasingly shaped by pragmatism, caution, and a desire to reduce dependence on an increasingly unpredictable Moscow.

Disillusioned partners: Armenia and Kazakhstan reposition

Among the CSTO members, Armenia and Kazakhstan stand out, for different reasons, as emblematic cases of growing disaffection with Russia’s security architecture. While differing in style and trajectory, both states have, in the aftermath of recent geopolitical shocks, begun to re-evaluate the value of CSTO membership, and by extension, their broader dependence on Moscow. These shifts reveal the fragility of the CSTO internal cohesion and the evolving strategic political calculus of states that once viewed alignment with Russia as a vital necessity.

Armenia's break with the CSTO expectations has been especially explicit. Historically aligned with Russia and heavily dependent on Moscow for military and diplomatic support, Armenia has increasingly questioned the credibility of CSTO commitments. The lack of support by the alliance during the 2020 Nagorno-Karabakh war against Azerbaijan was a focal event. The military success of Baku, supported by Turkey, saw no intervention by Moscow troops, which eventually stepped in to broker a ceasefire but on its terms. The situation even worsened in 2022 when clashes erupted along the Armenia-Azerbaijan borders.

Once again, Yerevan's appeals to the CSTO were followed only by symbolic responses which translated into monitoring missions, and statements of concerns, but no military assistance. For many observers, especially in Armenia, this confirmed that the CSTO guarantee, especially after the outbreak of the war in Ukraine, was only formal. Prime Minister Pashinyan has openly criticized the alliance, suspending participation in joint drills and pulling out of planned military exercises. Consequently, Armenia has turned westwards, hosting exercises with U.S. and NATO members' military forces and building stronger ties with the European Union.

Kazakhstan's political path, even if more cautious, is no less telling. The social unrest which broke out in early 2022, obliged President Tokayev to ask for Moscow's assistance, and the Russian-led forces, quickly deployed, managed to stabilize the situation. Despite the successful intervention, in the months following the Russian invasion of Ukraine, Astana made clear that it would not recognize the separatist republics in Donbas and had no intention of endorsing the war. Expanding its ties with other regional partners, namely China, Turkey, and the European Union, Astana has carefully avoided becoming entangled with the war, demonstrating its political pragmatism and the will to build an autonomous and multi-vector foreign policy. Through infrastructure projects, energy cooperation, and regional diplomacy, Kazakhstan is diversifying its alliances — and making sure it is not overly reliant on any one power, least of all one at war.

In this context, both Armenia and Kazakhstan, suggest a growing awareness across the CSTO: that the security umbrella once held firmly by Russia is full of uncertainties, and that the future may lie in a more flexible, multipolar approach. The once assumed loyalty to Moscow is now being weighed against national interest — and increasingly, found wanting.

Unsteady alliances and uncertain futures

While Armenia and Kazakhstan represent the most evident shifts within the CSTO, the other members, Belarus, Kyrgyzstan, and Tajikistan, present a more complex picture. Their continued participation in the alliance does not necessarily imply confidence in its long-term relevance. Membership, in this case, reflects a lack of viable alternatives, and an attempt to navigate internal vulnerabilities through proximity to Moscow.

As demonstrated since the outbreak of the war in Ukraine, Belarus remains the most openly aligned partner of Russia. President Alexander Lukashenko has not only repeatedly and publicly endorsed Moscow’s position on Ukraine but has also facilitated Russian military operations from Belarusian territory. In return, Minsk has received financial assistance, security guarantees, and regime support, a lifeline following the 2020 protests that threatened Lukashenko’s rule. However, this alliance is increasingly one of necessity rather than choice. Belarus is diplomatically isolated, economically dependent, and politically constrained. Its commitment to the CSTO does not depend on shared strategic interests but on the regime’s survival calculus. As for the majority of the CSTO members, Minsk has become more of a subordinate partner than an equal member of a collective defense pact.

As regards Central Asia, Kyrgyzstan and Tajikistan, by contrast, face different pressures. Both countries are historically heavily reliant on Russia for remittances, labor access, and military cooperation. Yet their bilateral tensions, most recently expressed in violent border clashes in 2021 and 2022, have underscored the CSTO's inability to function as a neutral arbiter among its members. The alliance failed to mediate or de-escalate these intra-bloc conflicts, reinforcing perceptions that it lacks the institutional capacity and the political will to address regional instability when Russia has no direct interest at stake.

At the same time, as for Kazakhstan, both Bishkek and Dushanbe have gradually opened to external partners. Chinese investment within the Belt and Road initiative has grown substantially, particularly in infrastructure and energy supported by regional institutions such as the Shanghai Cooperation Organization (SCO) offering overlapping forums for diplomacy and coordination. Although neither country has openly challenged CSTO membership, there is a quiet pragmatism: the alliance is tolerated, even used when convenient, but not regarded as indispensable.

These dynamics point to a broader decline in the CSTO’s strategic coherence. Formally intact, the organization appears intrinsically and increasingly fragmented in substance. Its members vary in their degree of alignment with Moscow, and their underlying threat perceptions, regional interests, and diplomatic orientations. For Russia, this fragmentation poses a serious challenge. Once envisioned as the institutional backbone of its regional security system, the CSTO now functions more as a symbol of former influence and soft power heritage than a mechanism of active coordination.

The CSTO in the years ahead could face three different scenarios. The first is a slow decline into irrelevance, a formal survival without strategic purpose, as members continue to drift apart while maintaining nominal affiliation. The second is selective consolidation, where a smaller core (e.g., Russia and Belarus) strengthens bilateral military ties while the broader organization fades. The third, the least probable, but not impossible, is a partial revitalization, contingent on large reforms, renewed resources, and an improved regional security environment. Given the war in Ukraine, Western sanctions, and Russia’s overstretched military, this third path appears increasingly out of reach.

The erosion of the CSTO reflects more than a crisis of one institution. It signals the gradual unraveling of a post-Soviet order built on Russian centrality, an order now being contested not only by external actors like China and Turkey but by the shifting priorities of the region’s states. For many CSTO members, the alliance no longer answers the most pressing questions of security and sovereignty. What replaces it remains uncertain, but the era of uncontested Russian leadership in Eurasia is drawing to a close.