Disputed Status of NK in the 1918-20 Period edit
Azerbaijan and Armenia submitted the dispute over NK and other areas to the allies, and the dispute wasn't resolved when Soviets arrived. Indeed, we have the Sevres treaty of August 1920:
ARTICLE 92.
"The frontiers between Armenia and Azerbaijan and Georgia respectively will be determined by direct agreement between the States concerned."
"If in either case the States concerned have failed to determine the frontier by agreement at the date of the decision referred to in Article 89 (i.e. when Wilson draws the map of Western Armenia--TTG), the frontier line in question will be determined by the Pricipal Allied Powers."
http://www.lib.byu.edu/~rdh/wwi/versa/sevres1.html
This fact is reflected in reputable sources as well:
"Nagorno-Karabakh first emerged as a disputed territory between Armenia and Azerbaijan when both states became independent in 1918. The dispute was not resolved until 1920, when both young nation-states lost their independence to Bolshevik Russia."
http://www.usip.org/pubs/peaceworks/pwks19/chap3_19.html
"Throughout January and February [of 1920] Armenia was embroiled in her struggle with Azerbaijan, carrying on a guerrilla war in the disputed and cross-populated areas." Christopher J. Walker. Armenia: The Survival of a Nation, p 282
Since Azebaijan had to demand NK even in 1920, obviously NK was not part of it, and was disputed:
"The relentless Soviet Azerbaijani demands for Karabagh and Zangezur were part of the logistical battle to secure a link between Soviet and Kemalist forces." Christopher J. Walker. Armenia: The Survival of a Nation, p 283
"From 1918 to 1920 Nagorno Karabagh possessed all necessary attributes of statehood, including an army and legitimate authorities. The League of Nations and the leading world powers recognized the disputed status of Nagorno Karabagh. The League of Nations neither recognized the sovereignty of the Azerbaijan Republic over Karabagh nor accepted the Azerbaijan Republic as its member-state." http://www.nesl.edu/center/pubs/nagorno.pdf
"[in 1920] the Ninth Karabagh Assembly nullified the treaty in whole and pronounced union with Armenia." http://www.nesl.edu/center/pubs/nagorno.pdf
"On January 15, 1920, the entente powers recognized de facto, that it is as a matter of fact, the Azerbaijan republic as an independent country. ... As distinguished from de jure recongition, that is as a matter of law, the de facto nature of the recognition admitted that there was doubt or an unresolved issue." A Diplomatic History of the Caspian Sea,Guive Mirfendereski, Palgrave 2001 p. 101
This is from www.atlas-of-conflicts.com:
For 1918: "Regardless of the Batumi treaty some Armenian troops under general Andranik continued to conduct guerrilla operations against the Turks from the mountain areas of Karabakh-Zanghezur, where another de-facto independent Armenian state had been proclaimed"
"The fragile peace with an unresolved territorial dispute a its background did not last long and the series of Azeri-Armenian wars broke out at the very end of 1918."
"In early March of 1920, regular troops of Azerbaijan attempted to suppress the Armenian-controlled enclaves in Karabakh. That triggered the outbreak of armed clashes all over Karabakh, as well as Naxcivan and Ordubad districts. "
http://www.atlas-of-conflicts.com/areas/armenia-and-karabakh/armenia-1919-20.php
Even pro-Azeri Cornell admits the continuous dispute.
"Meanwhile guerrilla fighting went on, especially in the mountains, as the Dashnaks never accepted this arrangement [i.e. appointment of Azeri governor]"
"the Red army entered Baku in April 1920, as the Azerbaijani army was locked up in Karabakh fighting an Armenian uprising"
http://www.silkroadstudies.org/new/inside/publications/1999_NK_Book.pdf