He believed that in the case of forgotten original reasons for war, the use of violence is going to be irrational. In addition, in order to be usable, war has to be limited. Not all unlimited wars are usable or productive for civil purposes. However, history experienced during the last two hundred years several developments like industrialization or enlarged warfare, exactly going in the direction that Clausewitz had feared. In fact, he warned that militarism can be extremely dangerous for humanity – a cultural and ideological phenomenon in which military priorities, ideas, or values are pervading the larger or total society (for instance, Nazi Germany).

The Realists, actually, accepted Clausewitz’s approach, which later after WWII, was further developed by them into a view of the world that is distorted and dangerous, causing the so called “unnecessary wars”. In general, such kinds of wars have been attributed to the US foreign policy during and after the Cold War around the globe. For example, in South-East Asia during the 1960s the US authorities were determined not to appease the Communist powers the way the German Nazis had been in the 1930s. Consequently, in attempting to avoid a Communist occupation of Vietnam the US became involved in a pointless and, in fact, unwinnable war, arguably confusing Nazi aims of geopolitical expansionism with the legitimate post-colonial patriotism of the people of Vietnam.