While the desire to preserve the European balance of power was undoubtedly a crucial factor leading to the First World War, to claim it was the essential cause would be to ignore a complex web of other powerful forces.

The principle of balance of power was indeed central to 19th-century European diplomacy. The unification of Germany in 1871 and its subsequent rise as a formidable industrial and military power fundamentally disrupted this equilibrium. Nations like Britain, France, and Russia perceived Germany's ambitions, particularly its naval expansion and "Weltpolitik" (world policy), as a direct threat. In response, they formed the Triple Entente to counteract the German-led Triple Alliance. Britain’s entry into the war, ostensibly to protect neutral Belgium, was fundamentally a strategic move to prevent Germany from dominating the continent and its coastlines, a classic balance-of-power consideration.

However, this political framework was loaded with other volatile elements. Aggressive nationalism was a potent force, from French desire for revenge over Alsace-Lorraine to Pan-Slavism inflaming the Balkans, which ultimately provided the war's spark. Furthermore, rampant imperialism fueled intense competition for colonies, resources, and markets, creating friction far beyond Europe, as seen in the Moroccan crises.

Finally, the pervasive culture of militarism, characterized by a continental arms race and rigid mobilization plans like Germany's Schlieffen Plan, created a situation where diplomacy had little room to maneuver. Once the first moves were made, the military timetables all but guaranteed a full-scale conflict.

In conclusion, the balance of power provided the geopolitical stage and the main actors. But the script of the war was written by the explosive interplay of nationalism, imperialism, and militarism, making it incorrect to view the conflict through a single lens.