This latest outbreak of fighting erupted due to shifts in the "power differential between Armenia and Azerbaijan" and the fact that "regional and global geopolitics were getting too unstable for the status quo to hold," explained Cornell. The conflict first erupted in the late 1980s between the Soviet republics of Armenia and Azerbaijan over the Nagorno-Karabakh enclave inside Azerbaijan, which is majority ethnic Armenian. Armenians in Nagorno-Karabakh wanted unification with the Armenia but faced resistance from Moscow as well as from Azerbaijan.
As the conflict escalated into a war between the two republics as the Soviet Union collapsed, Russia intervened in support of Armenia against the nationalist-led Azerbaijan Republic. Armenia, although three times smaller than Azerbaijan and lacking its enormous natural resources, won the war and took control of Nagorno-Karabakh and its population of 150,000, as well as seven other nearby provinces populated by approximately 700,000 Azerbaijanis.
Armenia's success was attributable to internal turmoil in Azerbaijan, Russian support, and the failure of Turkey to intervene on behalf of Azerbaijan. By taking over such vast territory, "Armenia bit off more than it could chew," Cornell said. Azerbaijani society refused to reconcile itself to the loss of Nagorno-Karabakh. As Azerbaijan became enriched with petrodollars in the years that followed, it spent massive amounts on building its military. "The disparity between the two parties to this conflict increase[ed]," to an extent that the status quo "was no longer sustainable ... something had to give."
The status quo held as long as it did largely due to geopolitical circumstances. Turkey and Israel – which were strategic partners in the 1990s – supplied military equipment to Azerbaijan, while "Russia and Iran supported Armenia in order to ... prevent Western and Turkish influence from spreading into the ... Caucasus of Central Asia." Even though Turkey has turned Islamist under Erdoğan, Azerbaijan still manages to maintain positive ties with both Turkey and Israel. The status quo held so long as outside players restrained their clients.
Turkey, in particular, became less willing to do so as a result of the "prominence" nationalist factions have assumed in Turkey since the attempted coup against Turkish President Recep Tayyip Erdoğan in 2016. Turkish nationalists in the military and state institutions see Russia as Turkey's historical adversary. Erdoğan has of late been provocative in his dealings with neighboring Greece, Cyprus and the Aegean; now he has taken the same approach to developments in the Caucasus.
Cornell said that the most important factor in the timing of the latest round of fighting was "the change in Armenia's positioning in this conflict." As a result of the 2018 Velvet Revolution, opposition activist Mr. Nikol Pashinyan came to power as prime minister. Pashinyan initially sought to restart peace negotiations with Azerbaijan but insisted that Nagorno-Karabakh should have separate representation in peace talks. At the same time, he provocatively announced, "Karabakh is Armenia," at a time when Azerbaijan's rhetoric warned of military action if negotiations were fruitless.
Armenia miscalculated by depending too heavily on Russia's protection from military confrontation with Azerbaijan. Russia considers Azerbaijan a strategically important country in the Caucuses and does not want to antagonize their relationship. Russia also took a dim view of Velvet Revolutions and had no qualms about Pashinyan being cut down to size in the conflict. As long as the fighting took place on the internationally recognized territory of Azerbaijan, Russia was content to limit its involvement to selling arms to Armenia. Russia's traditional modus operandi is "try[ing] to use the conflict [to] increase its influence on both sides." Cornell speculated that Moscow hopes "insert Russian peacekeepers into the conflict zone" (which in fact since happened under the recent cease-fire agreement).
Cornell argued that permanent solution to the conflict will require the U.S. and the European Union (EU) to take on the role of lead mediators, as they are the only honest brokers acceptable to both Armenia and Azerbaijan. Both the U.S. and the EU have a strong interest in "creating a stable land bridge between ... Europe and Central Asia" and "making sure that governments in the Caucasus countries are able to make their own decisions." Without a high-level of international involvement to find a long-term solution in lieu of ceasefires, episodic wars between Armenia and Azerbaijan will continue to erupt.