The question of whether the Caspian is actually a sea or a lake can seem silly. In reality it is not at all. The lakes are governed by International Law as internal waters and allow two things: to exclude the right of harmless passage of ships from foreign countries; make the exploitation of the exclusive resources of coastal countries.
The Russian conviction that the Caspian, in the face of its salinity, is a lake and not a sea, it is in this direction. On its surface, the joint maneuvers between the Russian and Iranian navy change the roots of Eurasian geopolitics. It does not even go too far these days, and the process does not seem casual.
First things first.
For some years IRIN (Islamic Republic of Iran Navy) and IRGCN (Islamic Revolutionary Guards Corps Navy) play an important role in the development of Iran's strategic capacity on a non-regional scale. If in the '80 years the naval activity was limited to the Persian Gulf with the occupation of the Tunb islands claimed by the United Arab Emirates (they are still today), to the raids of the boats of Pasdaran and the continuous threat of blockade of the Strait of Hormuz, the turmoil recorded in the Caspian Sea in recent months, suggests a strategic thought. Aware of its role in a crucial area for the political balance of the entire globe, Teheran moves.
The launch in the 2013 of the Damavand frigate (Jamaran 2) at Bandar-e Anzali in the Caspian Sea in this respect was very significant. With the support of Russia and China, Iran has succeeded in implementing its own "do-it-yourself" arsenal, combining the support of foreign partners with the decades-long experience of military and industrial autarky that has been forced from the birth of the Republic onwards. 
Beyond national pride, the new "front" on the Caspian however does not seem accidental. Under the cover of the defense of the maritime area linked to hydrocarbons and the caviar industry, Tehran is actually developing an entire reorganization of its naval capabilities, crucial to make operational the never hidden international political ambitions. If the trade with China, although characterized by important military contents, remains an essentially economic process for Beijing (the Chinese are thirsty for Persian crude oil), the intertwining with Moscow has a much deeper value. For the Russian navy, Iran provides support at the Bandar Abbas base, the gateway to the Persian Gulf and a thorn in the side for forty years for commercial (and military) navies throughout the West. The stopover is essential for Russian transfers from the Pacific bases to the Mediterranean ports, especially those of Tartus and Latakia in Syria. The possibility of bypassing the Turkish-occupied Bosphorus and of course the Polar Circle represents a millennial goal for the Russians.
Tehran's naval reorganization is therefore part of a long-term joint strategic vision. The intensity of relations between Iran and Russia are proof of this. The two diplomacies already enjoyed preferential lanes in the times of the USSR; now that Russian communism has waned and Persian theocracy has softened, the opportunity to push America's shaky foreign policy in the Middle East has become more than ever greedy.
The joint maneuvers in the Caspian Sea between Iranians and Russians reiterate a concept already waved last October 7 with the launch of Russian surface-to-surface missiles to targets in Syria. 
If Moscow has demonstrated ballistic capabilities with a smaller tonnage tank than the already known Gepard frigates (Buyan Corvettes), the Iranian development of a slim yet technologically advanced navy can be a source of further concern for US geopolitical strategies in the Eurasian bloc.
Whether the Caspian Sea is a lake or a sea at the bottom, it does not make much difference. What matters is who has control. Without prejudice to the Azeri coast, the Russia-Iran axis monopolizes the entire area. Turkmenistan needs Iran to build gas pipelines to the east that do not pass through Afghanistan and Pakistan; Kazakhstan falls within the sphere of influence of Russia with which it shares inter alia customs union agreements.
It is therefore evident that from Central Asia to the shores of the Indian Ocean the Russian-Iranian military political axis is growing strongly. Not new from the "ideological" point of view, on the other hand, it appears to be interesting in the light of the current situation in the Middle East and the lack of flexibility in decision-making demonstrated repeatedly by Western powers or former powers.
Between the Caspian and the Persian Gulf, all that remains is to wait.
[read also "Islam against Islam. Iran becomes necessary"]
(photo: Военно-Морской Флот Российской Федерации / Irna)
