All this has happened before, unfortunately

One of the few things Kaiser Wilhelm II, who ruled Germany from 1888 to 1918, had a talent for was causing outrage. A particular speciality was insulting other monarchs. One of the many things Wilhelm was convinced he was brilliant at, despite all evidence to the contrary, was 'personal diplomacy,' fixing foreign policy through one-on-one meetings with other European monarchs and statesmen. In fact, Wilhelm could do neither the personal nor the diplomacy, and these meetings rarely went well. The Kaiser viewed other people in instrumental terms, was a compulsive liar, and seemed to have a limited understanding of cause and effect.

Wilhelm was a compulsive speech-maker who constantly strayed off script. Even his staff couldn't stop him, though it tried, distributing copies of speeches to the German press before he'd actually given them. Unfortunately, the Austrian press printed the speeches as they were delivered, and the gaffes and insults soon circulated around Europe.

The general staff of the German Army agreed the Kaiser couldn't 'lead three soldiers over a gutter.' He had neither the attention span nor the ability. 'Distractions, whether they are little games with his army or navy, travelling or hunting -- are everything to him,' a disillusioned former mentor wrote. 'He reads very little apart from newspaper cuttings, hardly writes anything himself apart from marginalia on reports, and considers those talks best which are quickly over and done with.'

During Wilhelm's reign, the upper echelons of the German government began to unravel into a free-for-all, with officials wrangling against one another. 'The most contradictory opinions are now urged at high and all-highest level,' a German diplomat lamented. To add to the confusion, Wilhelm changed his position every five minutes. He was deeply suggestible and would defer to the last person he'd spoken to or cutting he'd read -- at least until he'd spoken to the next person.

More sinisterly, Wilhelm's patronage of the aggressive, nationalistic right left him surrounded by ministers who held a collective conviction that a European war was inevitable and even desirable. The Kaiser wasn't singly responsible for the First World War, but his actions and choices helped to bring it on. If international conflict is around the corner, it would seem you really don't want a narcissist in control of a global power. Wilhelm's touchiness, his unpredictability, his need to be acknowledged: These things struck a chord with elements in Germany, which was in a kind of adolescent spasm -- quick to perceive slights, excited by the idea of flexing its muscles, filled with a sense of entitlement. 

At the same time, Wilhelm's posturing raised tensions in Europe. His clumsy personal diplomacy created suspicion. His alliance with the vitriolic right and his slavish admiration for the Army inched the country closer and closer to war. Once the war was actually upon him, the government and military effectively swept the Kaiser aside. And the gravest damage occurred only after Wilhelm abdicated, in November of 1918. (He spent the rest of his life -- he survived until 1941 -- in central Holland.) The defeated Germany sank into years of depression, resentments sharpened, the toxic lie that Germany had been 'robbed' of its rightful victory in the war took hold. The rest, as they say, is history.

https://www.newyorker.com/culture/culture-desk/what-happens-when-a-bad-tempered-distractible-doofus-runs-an-empire