World War I was a torrid time and as Phillip Bobbit in The Shield of Archilles and Niall Fergusson in The War of the World tell it it was not a war from 1914-1918 but the start of a long war from 1914 to 1990. That was the war between totalitarian world views (both "communist" and "fascist") and democracy.
The first totalitarians to lose were the three great empires of Germany, Austro-Hungary and the Ottomans.
News today that the last heir to the Austrian throne has died. Born in 1912 Otto von Hapsburg evidently only officially relinquished his claim to the throne in 1961. He did great work to promote European unity, something that his grandfather perhaps should have thought about more.
His father - the last Emperor - evidently tried to organise a separate peace, but ultimately I think learnt the limitation of his power. His proclamation in 1918 that he no longer intended to rule he said was not an abdication, writing later "I did not abdicate, and never will. (...) I see my manifesto of 11 November as the equivalent to a cheque which a street thug has forced me to issue at gunpoint. (...) I do not feel bound by it in any way whatsoever."
There is a degree of arrogance in the fact that it took till 1961 for Otto to effectively complete the abdication. Interestingly, of course, such a relinquishing of the right to the throne only affects him and his heirs and successors, as it did for Edward VIII. Under standard succession rules there is probably still someone who could claim the "right" to the throne.
All of which ignores the fact that real power has always come from "the people". The apparent orderly succession of monarchs through inheritance has been disrupted as many times as it has been observed - especially in the UK.
Novae Meridianae Demetae Dexter delenda est