What was the most important single cause of the First World War, and why do you see it as such?

What was the most important single cause of the First World War, and why do you see it as such?

1. What was the most important single cause of the First World War, and why do you see it as such? My personal opinion of what was the most important single cause of the First World War was, Militarism. Militarism is a system that emphasizes the importance of military powers. Militarism alone did not cause the First War but it caused an environment where causing war was better than negotiating. During this time military power was very important to the states it represented. States needed a powerful military so it could support and protect their policies, defend them, and trade. War was expected by many Military officials because they were given such great influences in civilian governments.