Militarism is the belief that a country should have a strong military capability and be prepared to use it aggressively to defend or promote its interests. In the context of World War I, militarism was a powerful force in 19th and early 20th century Europe, where it was defined as the “domination of the military man over the civilian, an undue preponderance of military demands, an emphasis on military considerations”. Militarism alone did not start World War I, but it fueled a potent arms race and undermined the role of diplomacy as a means of resolving disputes.

Militarism caused nations to build up their armies and led to increased tensions between the European powers, especially in the arms race and naval race that occurred before the start of World War I. It also shaped culture, the press, and public opinion, with newspapers holding up military leaders as heroes, painting rival nations as dangerous aggressors, and regularly speculating about the possibility of war.

In summary, militarism in World War I was the belief or system where the military was exalted and its needs and considerations were given excessive importance or priority. It was a powerful force that contributed to the buildup of armies and increased tensions between European powers, ultimately leading to the outbreak of war.