The origins of World War One are a long standing point of contention among historians. The immediate trigger is obvious and well known: the murder of Franz Ferdinand, but really this is only a single manifestation of a wider set of problems sometimes known as the M-A-I-N causes (Militarism, Alliances, Imperialism and Nationalism). Among the warring nations 4 tend to stand out as most likely to have been responsible.
In many ways Serbia’s conduct in the early days of the war makes it seem an innocent victim of Austrian aggression; they mostly accept Austria’s ultimatum, they’re unjustly accused of sponsoring the terrorists who killed Franz Ferdinand and finally they are invaded by a much stronger power. Serbia, however, had been a focal point for nationalist agitation in the Balkans for a long time. It had already gone to war with the Ottoman Empire to expand its territory and the young nation’s exuberant nationalism made those around it nervous.
Germany is often blamed for World War One but usually for the wrong reasons. Contrary to the myth established in the War Guilt Clause of the Treaty of Versailles Germany’s interest in the war was not part of a wider expansionist programme nor was their militarism exceptional when comapred to other nations. Instead Germany’s responsibility derives from their strategy in the first weeks of the war which brought in countries involved at that point. The clearest example of this aggressive strategising is the Schlieffen Plan which brought Belgium, France and eventually Britain into the war. Germany may not have been responsible for the war itself but it was instrumental in launching it onto a global scale.
Of all the countries involved in the war Austria is the most obviously culpable, after all they were the first nation to issue a declaration of war. They rejected offers of mediation from other countries in favour of an aggressive assertion of their imperial interests in the Balkans.
Although Austria was the first nation to declare war Russia was the first major power outside of the direct Austian-Serbian conflict to mobilize so can be seen as responsible for escalating the situation. Russia’s refusal to stand down its mobilized forces was in turn what caused Germany to declare war on Russia and consequently, its triple entente ally France.
These countries are the ones with the clearest cases against them but almost every country involved has been held responsible for causing, escalating or prolonging the war at some point. As the M-A-I-N model explains the roots of the war lay in a particular political mentality which imagined war to be beneficial to the state and this kind of thinking was not at all restricted to any one nation.