There were several long-standing causes of World War II, including:

1. Treaty of Versailles: The harsh terms imposed on Germany after World War I, including massive reparations payments and territorial losses, created a sense of resentment and humiliation among the German people. This led to a desire for revenge and a rise in nationalism, which ultimately contributed to the outbreak of World War II.

2. Rise of Fascism and Nazism: The economic and political instability in Europe during the interwar period provided fertile ground for the rise of extremist ideologies, such as fascism in Italy and Nazism in Germany. Leaders like Benito Mussolini and Adolf Hitler exploited these conditions to gain power and promote aggressive expansionist policies.

3. Appeasement Policy: The policy of appeasement pursued by Western democracies, particularly Britain and France, towards aggressive actions by Nazi Germany and other fascist powers, allowed Hitler to gradually expand his territory without facing significant opposition. This emboldened Hitler and further destabilized the European balance of power.

4. Failure of the League of Nations: The League of Nations, established after World War I to promote international cooperation and prevent future conflicts, proved ineffective in dealing with the aggressive actions of fascist powers. Its failure to take decisive action in response to events such as the Italian invasion of Abyssinia and the German remilitarization of the Rhineland undermined its credibility and contributed to the outbreak of war.

5. Economic Depression: The Great Depression of the 1930s, triggered by the Wall Street Crash of 1929, led to widespread economic hardship and social unrest. This created fertile ground for the rise of extremist ideologies and contributed to the breakdown of international cooperation and the rise of protectionism.

6. Imperialism and Colonialism: The competition among European powers for colonies and resources around the world created tensions and rivalries that eventually escalated into war. The desire for territorial expansion and access to resources, particularly in Asia and Africa, fueled conflicts and contributed to the outbreak of World War II.

7. Failure of Diplomacy: Diplomatic efforts to resolve conflicts and prevent war, such as the Munich Agreement in 1938, proved ineffective in deterring aggression. The inability of world leaders to find peaceful solutions to disputes and the breakdown of diplomatic channels ultimately led to the outbreak of war.

It is important to note that these causes interacted and reinforced each other, creating a complex web of factors that led to the outbreak of World War II.