In the first years of the Kingdom of Serbs, Croats, and Slovenes, the foundations were laid for a political crisis that later marked its entire existence until its collapse at the outset of World War II. One of the basic causes for this situation was the centralist policy implemented by the dominant political actors, despite the complexities and heterogeneity of the new state. This study analyses the direction and tempo with which this centralist system was built from 1918 to 1923, with a focus on the western regions which had been a part of the Austro‑Hungarian Empire until 1918, and whose political representatives most strongly opposed centralisation.