7.6 Causes of World War II

6 min readjanuary 22, 2023

Jed Quiaoit

Jed Quiaoit

AP World History: Modern 🌍

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Unlike its predecessor, World War II didn’t start because of the assassination of a significant leader, thankfully. However, we can pinpoint its spark to both recurring and new causes alike. Some of them are similar to WWI’s, such as militarism and imperialism, but others are unprecedented, like economic downturns and the rise of totalitarianism.

Unsustained Peace Settlement After WWI

The Paris Peace Conference failed to solve the problems of imperialism and proper accountability, leaving the former Allies and Central Powers in very awkward political and diplomatic situations. The conference could not address many of the underlying issues that had led to the outbreak of the war, such as the tensions between the major European powers, nationalist movements, and economic disparities. The conference also failed to create an effective system for maintaining peace and resolving disputes in the future.
Many of the major powers at the conference, including France, Britain and Italy, were primarily motivated by their own self-interest and territorial ambitions rather than a genuine desire for peace and stability. This led to a number of territorial disputes and power imbalances that would eventually contribute to the outbreak of World War II. Furthermore, the existence of mandates gave Hitler a reason to justify his invasions of German-speaking regions as a form of unifying his people - the “superior race” - under one flag.
Italy also felt left out in the reward distribution of the Versailles Treaty, hardly receiving any territories despite fighting for the Allies during WWI. This ultimately sparked nationalism and ambitions to acquire what they weren’t able to before under Benito Mussolini. In the same decade, Italy had already risen as a fascist dictatorship, clear evidence that the peace settlement was hardly effective in the long run.

Global Economic Crisis

The Great Depression led to the collapse of countless governments across the world, especially the US and Western Europe. The lack of government activity fermented chaos and resentment among locals who called for action. The Great Depression led to widespread economic instability and hardship, with high levels of unemployment, poverty, and social unrest. This economic instability led to a rise in extremist political movements, such as fascism and communism, which promised to restore order and prosperity.
Even after these sentiments were alleviated by the eventual end of the crisis, it is actually the main reason behind Adolf Hitler’s rise to power through his platforms to use imperialism as the key to restarting Germany’s economy. As recently appointed Chancellor of Germany at the time, his bold promises to get Germany out of reparation payments (WWI) and become a leading power in Europe won over the German populace, who felt bitter and cheated as the main group held accountable in the Treaty of Versailles.

Rise of Fascist and Totalitarian Regimes

As briefly mentioned earlier, fascism and totalitarianism proliferated and expanded mainly due to two reasons:
  • Discontent towards WWI peace settlement. Germany felt humiliated and cheated by the treaty. The war guilt clause placed sole responsibility for the outbreak of World War I on Germany and imposed heavy reparations on the country. This War Guilt Clause was seen by many Germans as an unjust and unfair punishment, and it contributed to a sense of resentment and injustice among the German people. The imposed disarmament was seen as an unjust infringement on their national sovereignty and an attempt to weaken Germany's military power. The country also faced international isolation, being left out of the initial formation of the League of Nations and the ban on entering a union with Austria.
  • The Great Depression and the global economic crisis. Capitalism is clearly not the most effective economic system, even after the war. Mussolini and Hitler sought alternatives, and they found their niches within fascism and Nazism (a form of fascism), respectively, to avoid a repeat of the depression that killed, starved, and crippled millions worldwide.

Hitler and Nazi Germany

Hitler and the Nazi Party effectively disseminated their ideology and won the allegiance of the German people through propaganda. They promoted a sense of solidarity and pride in their country by using catchphrases and symbols like the swastika. In order to promote their message and influence public opinion, they also used the media, such as newspapers, radio, and movies. Furthermore, Hitler and the Nazi Party used legal and illegal means to gain power. They participated in elections, but also used violence and intimidation against their opponents. They also used the legal system to suppress political opposition and dissent. Some historians argued that they went all the way to stage the fire at the Reichstag building (the German parliament) in early 1933. In any case, the Nazi party used the fire as an excuse to pass the Enabling Act, which gave Hitler dictatorial powers.
Before the outbreak of World War II, Hitler implemented a policy of rapid rearmament and military expansion in Germany. This included a significant increase in military spending, the reintroduction of conscription, and the buildup of the country's armed forces. Neighboring countries started to be concerned about Germany’s rapid mobilization, but they chose to remain passive with the hopes of it ending soon. Previous adversaries like France and Belgium issued warnings for Hitler to stop, to no avail. Seeing that Hitler won’t do anything dramatic, the entire world remained on its toes as they waited on what he'd do next. As long as he doesn’t invade anyone nearby, nothing’s going to happen, right?

Italy and Fascist Italy

Italy's rise as a fascist country before World War II was led by Benito Mussolini and his National Fascist Party (PNF). In the aftermath of World War I, Italy experienced economic and social turmoil, which created fertile ground for the rise of extremist movements such as fascism.
Mussolini and the PNF capitalized on this by promising to restore order and national pride, and by the early 1920s, the PNF had become a powerful force in Italian politics. In October 1922, Mussolini led a march on Rome, which resulted in the formation of a fascist-controlled government.
Once in charge, Mussolini put into effect a number of measures that strengthened his hold on the nation. These measures included the repression of political opposition, the creation of a secret police force, and the development of youth organizations that served to indoctrinate young Italians with fascist ideology. He also put into effect measures to strengthen the economy and promote industrial development, including public works initiatives and the establishment of state-controlled businesses.


During the Interwar Period, Japan consolidated its hold over Asia. Years before WWII started, it entered the Berlin Pact with Fascist Italy and Nazi Germany - a symbol of their agreement on solidarity, allied assistance, and splitting the bounty after the war. Known as the Axis Powers, they resolved to acquire more land and create a new balance of power that centers on their tripartite axis. For instance, Mussolini's aggressive foreign policy led to the invasion of Ethiopia in 1935 and the intervention in the Spanish Civil War in 1936, both aimed to increase Italy's territorial expansion and prestige.
Hitler began to secretly reoccupy the demilitarized Rhineland in 1936 and annexed Austria in 1938 through the Anschluss. Hitler also began to make territorial demands on Czechoslovakia, leading to the Munich Agreement in 1938, which allowed Germany to take control of the Sudetenland region. With allies at his side, Germany proceeded to annex Austria (Anschluss) in March 1939, to everyone’s shock. France and Britain condone this as a form of appeasement in exchange for Hitler’s word on not invading any territory any further. When he violated this promise by invading Poland in September 1939, the two western European countries finally realized that there was no other way around and promptly declared war on Germany. After 20 years of uncertain peace, the world appeared to be at war once again.

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