In 1911, California voters approved the constitutional processes of initiative, referendum, and recall. Through these processes, voters can adopt a change in law (an initiative), disapprove a law passed by the Legislature (a referendum), or remove an elected official from office (a recall).
Tigris if im not mistaken
The German Empire and Austria-Hungary were Allied within the Central Powers, So I assume it was the German Empire in this case, Which Declared war on Russia and France and was at war with Britain due to the Invasion of Belgium.
So the Answer is the German Empire.