Multiple lay historians who I've met have insisted that the borders of Azerbaijan and Armenia were deliberately drawn by prewar Soviet officials (possibly including Stalin himself) with the expressed or implicit goal of fostering potential instability and increasing Russian power over the Caucasus -- in the inevitable event of war, as caused by the borders, Russia would need to intervene, justifying direct military involvement in the region.
However, this sounds conspiratorial and overly complex. Did Stalin's government really draw deliberately "bad" borders for Azerbaijan and Armenia?
According to P.L. Dash in “Nationalities Problem in USSR: Discord over Nagorno-Karabakh,” Economic and Political Weekly 24, no. 2 (January 14, 1989)
"In early 1923, a commission with an Armenian majority under the chairmanship of Kirov was formed to finalise the fate of Nagorno-Karabakh. Then there were no popular efforts by Armenians to merge this territory with Armenia. Therefore the commission decided that Nagorno-Karabakh should remain in Azerbaijan. When the Transcaucasian federation was dissolved and all its component republics became independent on December 5, 1936, Nagorno-Karabakh, despite its Armenian majority, was retained within the territorial boundary of Azerbaijan. It was primarily because of economic reasons-that it was kept within that republic."
Essentially Dash argues that it was a convenient administrative decision. However there is a body of literature that contradicts this neat explanation of the ethno-federal borders of the USSR. Ethno-federalism was a foundational principle of Stalinist Soviet ideology because it was believed to be the best way to force the many disjointed peoples of the USSR, many of whom were perceived as being "backwards," to evolve their societies. However in many cases many of the promises of this system were never carried out in practice. While it would be difficult to find direct evidence that Stalin used the development of administrative and autonomous region borders to justify future "Russian" involvement (as Moscow implicitly controlled the fate of all nationalities and republics within the USSR anyway through party politics and the politburo) it is clear that the Stalin's nationalities solution did allow for a "divide and conquer" like strategy. A better example of this are the AR of Abkhazia and South Ossetia in neighboring Georgia.
there is, both Nakhichevan and Karabakh were majority armenian before soviet invasion. Now only karabakh is, because armenians fought back there
