What were the main causes of World War II?

The primary causes of World War II include aggressive expansionism, totalitarian regimes, and unresolved issues stemming from World War I. Following World War I, the Treaty of Versailles imposed harsh penalties and reparations on Germany, which created significant economic hardship and resentment among the German population. This discontentment facilitated the rise of Adolf Hitler and the Nazi Party, who capitalized on nationalistic sentiments and sought to overturn the treaty and expand German territory.

Additionally, the 1930s saw the proliferation of totalitarian regimes in Italy and Japan, which pursued aggressive expansionist policies. Italy invaded Ethiopia, while Japan aggressively expanded into Manchuria and China, demonstrating a willingness to use military force to achieve their objectives and challenge the existing international order.

These factors combined with the failure of collective security mechanisms, such as the League of Nations, to effectively address acts of aggression or provide a robust response to violations of peace, setting the stage for a global conflict. This context emphasizes how the combination of unresolved issues from the previous war and the rise of militaristic and totalitarian governments directly contributed to the outbreak of World War II.