Unit 7.2 — Causes of World War I

Topic 7.1 left the Balkans destabilized by Ottoman collapse and small nations newly independent after the 1912–1913 Balkan Wars. Topic 7.2 explains how that regional instability, combined with several long-building structural pressures across Europe, escalated into a war that eventually drew in much of the world. Historians organize the causes with a widely used acronym — MAIN (sometimes extended to MANIA to include the specific trigger) — and the exam wants each letter defined precisely, not treated as an interchangeable list.

Militarism: arms races as a structural cause

Militarism describes a state's deliberate buildup and prioritization of military power. In the decades before 1914, Britain and Germany specifically poured enormous resources into naval and land-force expansion, and this arms race created both the physical capacity for large-scale war and a political culture in which military solutions were treated as normal and even desirable — a structural precondition without which the other three causes below couldn't have escalated into an actual continental war.

Alliances: a system built to deter war that instead guaranteed a wide one

By 1914, Europe's major powers had locked themselves into two rival alliance blocs: the Triple Entente (Britain, France, and Russia) and the Triple Alliance (Germany, Austria-Hungary, and Italy). These alliances were originally intended to deter aggression by making any attack on one member costly for the whole bloc — but the same logic meant that once one member entered a conflict, its allies were treaty-bound to follow, converting what might have remained a small regional conflict into a general European war almost automatically.

Imperialism: competition abroad hardens rivalry at home

Recall Unit 6's imperialism — years of competition over colonial territory, resources, and prestige (Topics 6.1, 6.4–6.5) had already set European powers against each other well before 1914. This colonial-era rivalry didn't stay confined to Africa and Asia; it directly reinforced and hardened the same alliance blocs described above, since powers competing for colonies abroad had every reason to seek reliable allies in Europe as well.

Nationalism: the ideology from Topic 5.2, now destabilizing rather than founding states

Nationalism — the same ideology that justified the Atlantic revolutions in Topic 5.2 and that Topic 7.1 showed eroding Ottoman unity — cut two ways in 1914. Intense loyalty to one's own nation and ethnic group hardened public and governmental support for military action once conflict began, while nationalist movements among Slavic peoples in the Balkans (particularly Serbian nationalism) directly created the specific regional friction that provided the war's trigger.

The spark: Sarajevo, June 28, 1914

All four structural causes above created what historians often describe as a pressure cooker needing only a single spark — and that spark was the assassination of Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, in Sarajevo on June 28, 1914, by a Bosnian Serb nationalist. Austria-Hungary's subsequent declaration of war against Serbia in late July 1914 triggered the alliance system described above in rapid succession, pulling in Russia, Germany, France, and Britain within days. The exam-critical point: the assassination was the immediate trigger, not the underlying cause — a war this large required the MAIN factors already in place; the assassination only determined the specific timing and location of the spark.

Why this matters for the exam

Topic 7.2 rewards using MAIN (or MANIA) as an organizing structure while explaining how each factor connected to the others rather than listing them as isolated causes: militarism supplied the capacity, alliances supplied the escalation mechanism, imperialism hardened the rival blocs, nationalism supplied both public support for war and the Balkan friction from Topic 7.1, and the Sarajevo assassination supplied the specific trigger date and event. A strong causation essay explicitly distinguishes long-term structural causes from the immediate trigger — exactly the distinction Topic 6.8's causation skill trained you to make.

Sources: Albert.io AP World History Review, Fiveable — MANIA.