BTK railway

Both Iran and Russia are attempting to assert influence in the Caspian Sea region, but their recent miscalculations are provoking visible resistance.

Most recently, Azerbaijan’s sharp responses to Tehran’s accusations about hosting Israeli drones and to Moscow’s deadly police raid on Azerbaijani nationals in Yekaterinburg (followed by Baku’s cancellation of a Russian foreign ministry official’s visit) highlight that not only Azerbaijan but the entire Caspian Sea region, including Central Asia, is increasingly unwilling to play the role of passive buffer.

These incidents, while seemingly bilateral, illuminate deeper structural shifts: the waning deterrent power of old hegemons and the emergence of a new regional assertiveness grounded in multi-vectorism and cooperative plurilateralism.

The Central Asian states are quietly observing the evolution of affairs in the South Caucasus, and vice versa. With the Organization of Turkic States gaining coherenceand with multiple trilateral cooperative structures nested within it, the South Caucasus-Central Asia macroregion is increasingly shaped not by vertical power projection but by lateral linkages.

The word “unprecedented” is overused, but it is entirely accurate to observe that the emergence of the South Caucasus as a region relatively autonomous from larger neighborhood powers is without precedent.

The crucial geopolitical location of the South Caucasus between the Caspian Sea and the Black Sea, including its already deep and still-deepening links with Central Asia to the east and Europe to the west, makes the present-day evolution of the region one of those butterfly-wing-flapping phenomena that will have implications far beyond the local context, as the structure of the post–Cold War international system continues to evolve over the next two decades and undergoes transformation beyond.

What makes the situation fundamentally unique

It is instructive to begin with some brief historical background. Armenia, Azerbaijan, and Georgia had relative autonomy from both Russian/Soviet and Persian/Iranian spheres of influence only once before in the modern era. This was during the brief interlude from 1918 to 1921, when the three independent republics – the Democratic Republic of Georgia, the First Republic of Armenia and the Azerbaijan Democratic Republic – were established.

Before then, one must go back to the mid-10th through the early 13th centuries to find a time when the region was not wholly subject to Russian, Persian or other imperial spheres.

During that time, different regional state formations flourished with relative independence from both the Abbasid Caliphate (by then in decline) and Persianate hegemonies, while Moscow – then not even yet a principality – remained entirely external to the region. These South Caucasus state formations included the Bagratid Kingdom of Armenia, the Kingdom of Georgia,and various Caucasian Albanian and Artsruni principalities.

The region we now call Azerbaijan was then in a politically and ethnoculturally intricate transitional state, governed by different semi-autonomous dynasties such as the Shirvanshahs, who maneuvered among Arab, Persian and Turkic influences.

The vernaculars spoken across the South Caucasus formed a complex mix consisting primarily of Northwestern Iranian languages, Northeast Caucasian languages, Kartvelian languages (Georgian being the most prominent but not the only one), Armenian, Indo-Iranian languages and Turkic languages (including the early forms of what evolved into Azerbaijani Turkic).

The Byzantine Empire had a presence but did not exercise consistent control over the highland South Caucasus interior. Seljuk Turkic incursions began in the 11th century, but political fragmentation and local resistance excluded their hegemony until the Mongol invasions. These began around 1220 and effectively ended this era of South Caucasus autonomy.

Thus, leaving aside the three years following the end of World War I – too short to qualify as a “historical era,” properly speaking – the last time the South Caucasus was relatively autonomous from Russian, Persian and other spheres of influence was approximately 800 to 1,100 years ago: before the Mongol conquest and well before the flourishing of the Romanov, Safavid (and their successors) and Ottoman dynasties that define the emergence of the modern era in present-day historical consciousness.

From the South Caucasus to Central Asia

Jumping to the present, the South Caucasus today anchors a westward corridor of strategic depth for Central Asia, offering the only viable east-west transit alternative to routes passing through Russia or Iran.

Azerbaijan arguably serves as the linchpin of this corridor, the critical enabler without which the system would not function. Its territory hosts and integrates essential infrastructure linking Central Asia with Turkey and onward to Europe, not through rhetorical connectivity but via physical corridors that are already operational and expanding.

At the core is the Middle Corridor (Trans-Caspian International Transport Route, TITR), which originates in Kazakhstan, crosses the Caspian Sea and runs through Azerbaijan, Georgia and Turkey before entering European markets.

Following Russia’s invasion of Ukraine in 2022 and the re-imposition of sanctions, this route has gained heightened significance. The Middle Corridor is not merely a grand infrastructural vision; it rests on concrete, multilateral agreements and functioning multimodal logistics hubs.

A central node of the Middle Corridor is the Port of Alat, south of Baku, which accommodates container transshipment from maritime to rail and road traffic. It serves as the principal logistical hinge point between the trans-Caspian and South Caucasus transit systems.

The Baku–Tbilisi–Kars (BTK) railway provides a direct rail link from the Caspian basin to Anatolia and then to Europe, bypassing both Russian and Iranian territory. Its freight volume has significantly increased in recent years, particularly since early 2022. Its recently achieved capacity expansion and double-tracking of key segments establish it as a permanent artery of Eurasian transit.

The integration of Central Asia with the South Caucasus

Energy export infrastructure further increases Central Asia’s focus on the South Caucasus. The Southern Gas Corridor (SGC) – a non-Russian and non-Iranian energy vector – transports Azerbaijani natural gas from the Caspian Sea to European markets. The expansion of SGC throughput, including interconnectors into Balkan networks and now East Central Europe, reflects its geostrategic irreversibility.

Kazakhstan and Uzbekistan are embedding the South Caucasus further into Central Asian strategy through growing energy and transport cooperation. In 2022 and 2023, Azerbaijan and Kazakhstan signed successive agreements to boost oil transshipment via the Caspian, while Uzbekistan has similarly coordinated on containerized freight routes.

Trilateral and quadrilateral formats among Central Asian and South Caucasus states have begun to institutionalize regular coordination on such practical tasks as customs simplification, port throughput and freight schedule alignment.

Uzbekistan and even Turkmenistan – with the assistance of Kazakhstan and Azerbaijan – are now becoming integrated more integrally into the Middle Corridor. International financial institutions, which had originally targeted only Kazakhstan in Central Asia, are now extending cooperation to other states in the region.

This development complements the coordination of customs harmonization and digital documentation among Azerbaijan, Georgia, and Turkey to resolve non-physical bottlenecks to the west of the Caspian Sea.

From this perspective, it is clear that the South Caucasus no longer functions as a marginal buffer but is an active integrator of Central Asia into the broader Eurasian system.

Moreover, the region’s infrastructural and diplomatic initiatives no longer depend upon great-power patronage. Instead, they reflect an emerging Eurasian pluralism anchored in mutual interests realized through concrete investments. These dynamics point toward nothing less than a re-patterning of Eurasia’s modern-era geoeconomic core.

Toward the re-patterning of the Eurasian system

The infrastructural and diplomatic realignments across the South Caucasus and Central Asia are not isolated developments. They mark a reconfiguration of Eurasia’s internal architecture, in which the ability to coordinate across domains – transport, energy, customs and digital systems – now carries more strategic weight than traditional bloc alignments or alliance rhetoric.

These regional actors are not immune to external pressure, but their increasingly self-directed orientation reflects the slow erosion of vertical hegemonic structures in favor of horizontal operational linkages.

This re-patterning gains further significance in view of China’s growing presence in Central Asia. Rather than competing directly with Beijing, the South Caucasus offers a parallel route (complementary in many cases) for east–west exchange.

Azerbaijan’s role is emblematic in this regard: It does not challenge China’s infrastructural logic but instead mediates how external flows, including Chinese ones, connect to Western markets. This is a form of infrastructural agency that shapes the modalities and conditions under which regional and transregional integration takes place. Its function is one of filtering rather than resistance.

As the international system continues to shift through the late 2020s and into the 2030s, the Caspian region will increasingly matter, not just as a site of contestation between larger powers but as a space where smaller and middle powers consolidate meaningful influence. The logic of passive buffering is being replaced by active modulation.

The post–Cold War order may be bifurcating; it is not wrong to see, from a top-down structural perspective, a fundamental opposition between a US–led Anglosphere and a Chinese-led Sinosphere.

In the increasing disorder that will overtake the system’s macrostructure for a dozen years starting in the early 2040s, what will provide continuity is the differentiated system of coordination among second-tier actors, who will increasingly define regional coherence while constraining great-power projection.

Azerbaijan’s role in the emerging Central Asia–South Caucasus macroregion, indexed by its riposte against the recent hegemonic démarches by Russia and Iran, foretokens this broader re-patterning.