the four main causes of world war I were imperialism, nationalism, militarism, and entangled alliances. which of the four main causes do you believe contributed the most towards the start of world war I? Be sure to use evidence from the lessons to support your response

Among the four main causes of World War I — imperialism, nationalism, militarism, and entangled alliances — it is the entangled alliance systems that arguably contributed most significantly to the outbreak of the war. Alliances created a complex network of diplomatic and military commitments that bound countries to one another in a way that turned a regional conflict into a world war.

Evidence of this is found in the way the war started. The assassination of Archduke Franz Ferdinand of Austria-Hungary by a nationalist Serb in June 1914 set off a chain of events propelled by these alliance systems. Austria-Hungary, with the backing of Germany, gave Serbia an ultimatum, leading Serbia to seek support from Russia. Due to alliances, Russia's mobilization brought in its allies, including France and Britain, while Germany's support of Austria-Hungary brought in Italy and later the Ottoman Empire.

Had the alliance system not been so rigid and expansive, the conflict might have remained localized to the Balkans, rather than escalating into a global conflict. The alliance system meant that once one country became involved, several others were dragged along due to defensive pacts, and the 'domino effect' took place, escalating a regional conflict into a global war.