National Council of Slovenes, Croats and Serbs

This position was upheld by the Croatian Sabor meeting on 29 October to sever ties between Croatia-Slavonia, Dalmatia and the city of Rijeka on one hand and the Kingdom of Hungary and Austria-Hungary on the other.

Instead, the National Council sent a delegation to Serbia to request speedy unification, as it was facing pressure from widespread violence and disorder in the countryside and the advancing Italian Army.

A committee tasked with determining the country's war aims produced a programme to establish a Yugoslav state through the addition of Croatia-Slavonia, the Slovene lands, Vojvodina, Bosnia and Herzegovina, and Dalmatia,[3] echoing Serbian Foreign Minister Ilija Garašanin's 1844 Načertanije treatise anticipating the collapse of the Ottoman Empire, which called for the unification of all Serbs to pre-empt Russian or Austrian expansion into the Balkans.

[2] In 1918, the Yugoslav Club tried to bring together the political parties representing the South Slavs in Austria-Hungary in favour of the "national concentration" of Slovenes, Croats, and Serbs in a common state.

Due to lack of diplomatic experience, the council authorised the Yugoslav Committee, an ad-hoc group of politicians and activists, to speak on its behalf in international relations.

[14] After the Serbian government led by Nikola Pašić recognised the National Council as the legitimate representative of South Slavs living in the territory of Austria-Hungary,[15] a National Council delegation, led by its president Anton Korošec, took part (jointly with the Yugoslav Committee and Serbian parliamentary opposition) in negotiations with Pašić, and signing of the Geneva Declaration on 9 November to quickly unite the State of Slovenes, Croats and Serbs with Serbia in a confederal state.

[17] The urgency of unification increased as security deteriorated in the countryside because of the Green Cadres, and the Italian Army advanced following the collapse of Austria-Hungary and the Armistice of Villa Giusti.

By 17 November, Italian forces captured Rijeka and were advancing through Carniola, reaching the vicinity of Ljubljana—with the aim of enforcing the Treaty of London which promised Italy territorial gains in return for going to war against Austria-Hungary.

However, the list of its representatives was drawn up by National Council member and new government minister Albert Kramer on authorisation by the regent but without input from the relevant political parties.

[22] Shortly after proclamation of the Kingdom of Serbs, Croats and Slovenes, there was a protest of soldiers in Zagreb suppressed by forces organised and led by the National Council.

[24] Furthermore, the council cited the clash and the Lipošćak affair as grounds to restrict the inclusion of Croatian officers who previously served in the Austro-Hungarian armed forces in army of the new unified state as unreliable.

[27] The National Council originally intended to include 18 representatives from the regions of Međimurje, Baranya, Bačka, Banat, and Prekmurje, but those seats were left largely vacant.