Actually since you may find it of interest Marko, I'm going to post the whole section of the chapter that deals with the unification of Serbia, Montenegro, and the State of Slovenes, Croats, and Serbs in 1918. It's a very good book in my opinion because it brings to light many details about Yugoslavia's creation that I myself did not know about either. Here you go.
On October 29, 1918, the National Council of Slovenes, Croats and Serbs proclaimed itself the government of the new state of Serbs, Croats and Slovenes. 203 Its decision followed that of the Croatian Diet, which had on that day declared (p. 114 ) the end of “state-legal relations and connections” between the Triune Kingdom of Croatia, Slavonia and Dalmatia (which allegedly existed in the Middle Ages) and the Kingdom of Hungary and the Austrian Empire (Article I), and proclaimed this territory to be part of the (still not established) State of the Slovenes, Croats and Serbs, independent of Hungary and Austria (Article 2). 204 Significantly, the Croatian Diet based its decision “on the basis of the complete right of people's self-determination which is now recognized by all warring parties” (Article 1). On November 3, 1918, the National Council requested but never obtained recognition from the governments of France, Great Britain, the USA, and Italy. On November 8, 1918, only Serbia recognized the new government but not the state. 205 The same day Pashich sent a note to the Serbian diplomatic representatives in Paris, London, and Washington asking them to seek recognition for the National Council. Again the word “government” was used, not “state.” Moreover Pashich stated that the National Council would be considered “a government of Yugoslavs on the territory of the former Austro-Hungarian Monarchy until the definitive constitution of a single state of Serbs, Croats and Slovenes.” 206 Protich explains the Serbian act of recognition as “a sign of generosity towards a party whose status was, in the least, questionable.” 207
At the same time, the Serbian government did not consider the National Council to be on equal footing as negotiators of the internal organization of the new state. Pashich signed a declaration to that effect at the Geneva conference of November 9, 1918 (Geneva Declaration), 208 principally as a result of pressure stemming from the Serbian opposition parties. Nonetheless, a unified front was (p. 115 ) needed to demonstrate the impossibility of survival of the Austro-Hungarian Monarchy. 209 As Pashich explained to Stoyan Protich, the acting head of the Serbian cabinet, in a long telegram:
under the pressure of events I was faced with the alternative: yield at the expense of Serbia's reputation and my own or take upon myself the curse of the people because with our disunity we wrecked the unity of our people. 210
The Geneva Declaration refuted the Declaration of Corfu by failing to affirm that the new state would be a consititutional monarchy led by the Karageorgevich dynasty, proposing instead that a “common ministry of Serbs, Croats and Sloveness,” be composed of three members of the Serb government and three members of the National Council of Serbs, Croats and Sloveness, with a purpose of negotiating a new state arrangement and other relevant issues until the adoption of a new Constitution. The Serb Prince Regent refused to sanction Pashich's signature to the Geneva Declaration and Pashich's cabinet resigned. 211 In Zagreb, Svetozar Pribichevich, the leader of Serbs from Austria-Hungary, also opposed the agreement. The end result was that neither the Serb government nor the National Council accepted the ill-fated Geneva Declaration, a document that remained a draft proposal without legal effect. 212
It is important to note that the State of the Slovenes, Croats and Serbs was not formed for the sake of creating an independent state, but with a goal of establishing a representative body that would act on the unification of the Slav provinces of the Austro-Hungarian Empire with the Kingdom of Serbia. This is most clear in the decision of the Dalmatian National Council of November 16, 1918, declaring that the province of Dalmatia would unilaterally join the Kingdom of Serbia in the absence of overall unification. 213 As Hondius has pointed out, “the regional national councils were already threatening to join Serbia on their own accord.” 214
(p. 116 ) The process of establishing a joint government in the formerly Habsburg South Slav provinces was rushed, not entirely democratic and not entirely successful. While the Croatian Diet adopted a resolution to this end, it had jurisdiction over only two provinces—Croatia and Slavonia. The Slovenes elected a government only in October 1918, but indirectly—from the ranks of the Slovene People's Party and the National Progressive Party. In the provinces of Bosnia and Herzegovina, “the executive authority” became the National Council of Serbs, Croats and Slovenes for Bosnia and Herzegovina, also established only on October 20, 1918 from of the ranks of political parties that were also represented in the National Council in Zagreb. 215 While both the Slovene and the Bosnian national councils initially placed themselves under the jurisdiction of the National Council in Zagreb they did so solely with the purpose of entrusting one body to perform the process of unification with Serbia. That the Zagreb government was not a full-fledged government is also supported by a decision of the Voivodina assembly (then incorporating the provinces of Bachka, Banat and Baranya) of November 25, 1918, to directly merge with the Kingdom of Serbia, which was instantly accepted by Serbia. 216 The Kingdom of Montenegro also decided to unite with Serbia unilaterally and prior to the creation of the South-Slav 217 state, as did the forty-eight of the fifty four municipalities in Bosnia. 218 In Montenegro, the Great National Assembly also voted for Montenegro's unification with Serbia on November 13, 1918, reflecting the wishes of the majority population that elected the pro-unification delegates a month prior to this decision. The Assembly (p. 117 ) simultaneously dethroned the Montenegrin King Nicholas I and the Petrovich Nyegosh dynasty, accepting the rule of the Karageorgevich dynasty: 219
… Montenegro unites with its brother Serbia into a single State under the dynasty of Karadjordjevic and, thus united, enters the common fatherland of our threefold people of Serbs, Croats and Slovenes.…
… The Serbian people in Montenegro is of one blood, speaks one language and has the same aspirations, is of the same religion and has the same customs as the people that lives in Serbia and other Serbian lands. 220
However, even in Montenegro the question of unification was not posed directly to the population and very few delegates were opposed to the achieved terms of unification. 221 At the same time, the population of the Habsburg Carinthia region, the only province in which a direct vote was taken on the question of unification as a result of the Paris Conference, said ‘no’ to a Yugoslavia on October 10, 1920. Although two-thirds of the population was Slovene, only 41 percent of the total population in Carinthia desired a common South Slav State, which means that a significant number of Slovenes, like the Austrians of the region, desired to be part of Austria. 222 Some deduce from this plebiscite result that the majority of Slovenes, and perhaps even Croats, were of this opinion. Others believe that the Yugoslav movement was dominant among all South Slav peoples. No matter what the prevailing ideology, it is clear that the perceptions of the goal of the common Slav State were different among its component nations, as reflected in the ensuing argument over the constitution.
In Bosnia and Herzegovina, the National Council had, upon constitution, declared itself for union of all Yugoslav peoples, inviting Serbia's Fieldmarshall Stepa Stepanovich to liberate them from the Habsburgs. 223 On November 23, 1918, (p. 118 ) the Central Committee of the National Council in Zagreb proclaimed the unification of the State of Slovenes, Croats and Serbs with Serbia and Montenegro 224 and elected an implementing Committee. This Committee had little leverage when it arrived to Belgrade on November 28, 1918. Members of the National Council of Serbs, Croats and Slovenes were aware that the majority of the population they claimed to represent would no longer stand behind them if unification with Serbia were not achieved. Some of their nominally subordinate councils had already undermined their authority by deciding to join Serbia directly, such as the National Council of Voivodina and the majority of Bosnian municipalities as outlined above.
Late on 1 December 1918, the head of the delegation, Ante Pavelić (who was not the same Pavelić who later founded the Nazi Ustasha movement in Croatia) appeared before the Prince Regent Alexander and read an address that referred to a single state under the reign of the Serb monarch. At the occasion, Prince-Regent Alexander Karageorgevich proclaimed the Kingdom of Serbs, Croats and Slovenes, 225 and this was the only proclamation producing legal effect. After all, the provisional Zagreb Council and the Belgrade government were not equal partners. On 16 December 1918, the Serbian National Assembly declared to be “happy in being able to give its political confirmation to the accomplished fact of the political union of the Serbs, Croats and Slovenes” but with one important caution:
It trusts that the State frontiers will be drawn in such a way as not to impair our right of national self-determination and it expects the Government to defend this right to the uttermost. 226
In recognizing the Kingdom of Serbs, Croats and Slovenes, the Great Powers obligated the new state to guarantee language and religious rights, as well as other (p. 119 ) group rights, both for the three constituent nations and for “nationals who belong to racial, religious or linguistic minorities.” 227
The “new state” relied in the main on the legislation of the Kingdom of Serbia prior to the adoption of the new constitution in 1921. Whether the Kingdom of Serbs, Croats and Slovenes, formed in December 1918, is a new state or a continuation of the Kingdom of Serbia, is a question that has troubled many jurists. Slobodan Yovanovich argues that by international law, the Kingdom of Serbs, Croats and Slovenes is a continuation of the previous Serbian state, since only Serbia existed as a state to which remnants of the Austro-Hungarian Empire were joined, succeeding to all contracts and treaties of the Kingdom of Serbia. 228 However, Yovanovich also insists that by constitutional law, this was a new state, which had new state symbols, and to which a new constitution applied (once adopted in 1921), making no reference to the previous constitution. Others disagree with Yovanovich, who, although a respected lawyer, was also an ardent yugophile and thus biased in that respect. They argue that there was constitutional continuity since the new constitution of the Kingdom of Serbs, Croats and Slovenes was based on the liberal 1903 Serbian constitution and the Serbian Parliament was the only body to officially ratify the unification of the Kingdom of Serbia with the South Slav parts of the Austro-Hungarian Empire. Another argument in favor of those who claim the continuity of the Serbian state is that the Austro-Hungarian Slavs did not join at once but the region of Voivodina united with the Kingdom of Serbia several days earlier. 229 Montenegro also joined the Kingdom of Serbia prior to the December act of unification. Finally, the new common state of South Slavs was ruled by the same monarchy, the Serbian Karageorgevich dynasty. (p. 120 )