A horrible event shocks the world. The affected power, enraged, threatens war and gives an ultimatum. Looking around for allies, it’s given a “blank cheque” by its powerful patron – one of the great powers of the world. With that patron’s guarantee, the march to war starts. But the smaller power, about to be invaded, also has powerful allies, who mobilize their forces in turn. Once the mobilization and counter-mobilization begins, the march to war seems irreversible. Then, the power who wrote the blank cheque decides to strike first – pre-emptively, to try to take out one of its enemies before facing the others. We’re talking about 1914, and how WW1 started.