When Romania declared war on the Central Powers, what remained of the PȚD was further split. Doboș deserted to the Romanian side, then helped organized Romanian political clubs and a Volunteer Corps in the Ukrainian People's Republic. He himself noted that "many" of his colleagues in Dacia Society followed suit. In November 1917, Doboș joined Sever Bocu and Tomáš Garrigue Masaryk at the Congress of Nationalities from Austria-Hungary, held in Kiev. As Romania experienced heavy losses and its capital fell, Onciul radicalized his opinions on the issue of irredentism. He argued for the annexation of Romania to fulfill Romanian unity under one crown; he also called for Austria to cede its Ukrainian regions to a Ukrainian state, and for West Galicia to fuse into a German-aligned Poland.