It is no secret that the Caucasus has always been a hard to chew piece of land - not only for the Tsar-era Kremlin, but also for the communist-era Kremlin and the "democratic" thug-era Kremlin, despite the fact that for some time now the unyielding mountain men are being propitiated with the carrot, not the stick, as was the case in the nineties.
Eastern Europe, especially the Baltic states, can let out a brief sigh of relief while the Kremlin is preoccupied with its eternal fight against the armed Chechen opposition by investing huge amounts of money in Kadyrov's clan. And the socioeconomic situation in Russia's other Caucasian subjects, for instance, Dagestan, Ingushetia, North Ossetia, Abkhazia, Kabardino-Balkaria and Vladikavkaz, is far from being great; i.e., it is barely livable. Then there is the dispute between the Armenians and Azerbaijanis over Nagorno-Karabakh, which has been ongoing already since the collapse of the USSR, of course not without the involvement of the Kremlin. Putin's regime has always worked very hard to maintain influence in the region without sparing shame or resources, which are getting increasingly scarce each day.
You see, the Kremlin was able to maintain "harmony" between Baku and Yerevan for quite a while by dragging Armenia into the CSTO and other international organizations created by Putin, allowing him to advance his interests in the region - like a wolf among sheep.
Everything was fine for the Kremlin until a more powerful and shameless wolf appeared from Turkey and provided support to Azerbaijan. Turkey's engagement has seriously shaken up the "Caucasus chessboard" and comes at a time when Putin is recklessly damaging his own prestige and influence. In other words, Putin's carrot policy is no longer effective in the Caucasus, which is proven by the war between the ancient enemies - Azerbaijan and Armenia.
For the Kremlin, this is a serious challenge because not only the honor and prestige of the CSTO is at stake, but also its existence. I believe Nagorno-Karabakh is a hole accidentally created by the Kremlin itself in which the CSTO will fall into and disappear any time soon.
Formally, the CSTO does not have the authority to interfere because neither Nagorno-Karabakh nor Azerbaijan are members of the organization. While no one touches Armenia, the Russian army must remain idle, at least officially. Baku has clearly stated that it is interested only in regaining Azerbaijani land; i.e., only the internationally unrecognized Nagorno-Karabakh.
If the Kremlin decided to engage in resolving the conflict using force, it would be faced with certain problems. First, it would be nearly impossible for the Kremlin to supply its 102nd Military Base in Gyumri (Armenia). Second, this would immediately mean the Kremlin lost its status as a "peacekeeper" in the Caucasus region, and maybe this would even force some politicians in the Old Europe to open their eyes. But if the Kremlin decided it doesn't care about any of this, Nagorno-Karabakh would be doomed just like the role of Moscow as Yerevan's provider of security. And this would mean the end of the CSTO.
This conflict wasn't resolved back in 1992, when Moscow created the CSTO, but it was nonetheless decided to accept Armenia into the military organization. Now, when the geopolitical situation has drastically changed not in favor of Russia and when Putin has nearly ruined the "mighty" superpower, the war in Nagorno-Karabakh could create serious problems for the Kremlin's masters because the Kremlin would have once again betrayed its allies - the Armenians of Armenia.
What is more, the joint forces of Putin and Assad are more frequently suffering shameful losses in Idlib. It is rumored that Assad's funeral is scheduled for early 2021. And whenever someone mentions the successful strikes by Turkish drones in Libya in April, the hearts of the mercenaries working for the private military company Wagner - owned by Putin's chef Prigozhin - start beating a little faster.
It looks like Putin is not sure what to do, because if Turkey is triumphant in Nagorno-Karabakh it will expose Moscow's weakness and put an end to the existence of the CSTO: everyone in the Caucasus, except the Armenians, will want to be friends with Erdoğan. The small Muslim nations, long oppressed by Moscow, will want to do the same. And if the Kremlin decides to use force against the small nations of the Caucasus - and it is more than likely that this will happen - it will only escalate the situation and provoke radical terrorist attacks in Russia. Does anyone even know how many Russians are left, for instance, in Moscow?
All in all, it looks like the Kremlin is rapidly losing its political influence in the Caucasus. If Nagorno-Karabakh is brought under the control of Azerbaijan, it would spell the end of one of the longest conflicts maintained by Russia. In one way or another, the region will become pro-Western, and moreover Turkey is NATO and NATO is the US. You can draw conclusions yourselves.
One thing is certain: the war in Nagorno-Karabakh proves that the Kremlin is no longer able to handle external and internal "irritants", meaning that Russia has lost its status as a superpower. Its ratings as a "peacekeeper", just like the prestige of the CSTO in the Caucasus region, are inevitably falling deeper and deeper into one of Nagorno-Karabakh's chasms.
Meanwhile, the Kremlin's propaganda media outlets continue spreading illusions of grandeur based on Stalin's ideology, forcing the Russian ambassador in Latvia along with a handful of people shouting "Crimea is ours" to cross Ķīšezers and liberate Riga from made-up fascists. But now we can see that Moscow as the leader of the CSTO is unable to provide the promised military and political support to one of its closest military allies - even though all the contracts were solemnly signed long ago.
P.S. Article 5 of the CSTO is worthless!