Why political stability looks different in hindsight

Why did so many states appear less stable in the First World War than in the Second?

They were not necessarily less stable; hindsight makes failed crises look harmless and successful upheavals look inevitable.

Political stability was contingent in both world wars. A country can appear orderly until a movement succeeds, after which historians are tempted to reinterpret earlier tensions as inevitable causes. The Peasants' Revolt and political challenges under Henry VIII are examples of serious unrest that did not produce a civil war and is therefore often minimized. The methodological lesson is to identify a writer's starting and ending points and avoid treating the actual outcome as proof that alternatives never had a chance.