While many causes contributed to the Second World War, the political climate in the participating countries fostered hostility and revanchism, especially in Germany and Italy. Revolutions and internal tribulations also placed these countries in tough economic and ideological predicaments, leading to spillovers and an overall consolidation of conflict beyond international and continental lines.
Germany had been facing considerable restrictions through the Treaty of Versailles and had lost nearly a third of its original territories, along with the complete liquidation of the Prussian Empire. Following the German Revolution in the immediate aftermath of the First World War, the Weimar Republic—a rump state—was created and remained in place until 1933.
Undercurrents of humiliation and economic desperation ran rife in the populace, and the rise of National Socialism was underway. As the far-right portions of the German Workers’ Party indulged in the violent suppression of their communist foes, these units eventually led to the evolution of the party into the National Socialist German Workers’ Party, or the Nazi Party. Adolf Hitler took on the role of Fuhrer and replaced his former mentor, Anton Drexler, in 1921. Two years later, Hitler got embroiled in a failed attempt to overthrow the Weimar Republic; however, it wouldn’t be until 1933 that Hitler rose to absolute power in Germany.
Throughout the 1920s, radicalism and calls for reclaiming lost territories grew. Eventually, Paul von Hindenburg, the then President of the Weimar Republic, appointed Adolf Hitler the Chancellor. The former died soon after, in August 1934, following which Hitler promptly abolished the democratic republic and transitioned the state to a totalitarian dictatorial nation. Nazi Germany subsequently invaded numerous neighboring European nations, with the German state committing the worst case of genocide in human history—the Holocaust.
A similar totalitarian state also rose to power in Italy under Benito Mussolini, following the Italian Fascist Movement that extended from the early to mid-1920s. Italian ultras were dissatisfied, and calls for reclaiming what was rightfully theirs grew within the country. Italy was denied its rightful gains following the victory in the First World War, primarily because the United Kingdom and France refused to acknowledge its claims. With the Fascist Movement’s success, Mussolini became the state’s head and the leader of Italy during World War II. Italy, too, fell victim to ultranationalist, xenophobic, and totalitarian ideas despite its alliance with the Entente powers during the First World War. Expansionism pervaded the Italian state consciousness, and Mussolini’s government sought to build a new Roman empire based on its policies.
On the other hand, the situation in Asia was more complex, given that China faced an extensive civil war and the Empire of Japan sought territorial gains internationally. Japan’s imperialist forces commenced the invasion of Manchuria, which eventually coalesced into the Second Sino-Japanese War. A weakened China embroiled in internal turmoil was a perfect target for the Imperial Japanese Empire. The latter had also modernized rapidly in the previous several decades, seeking more resources and manpower to extend economic growth. With the nation being an isolated island, Japan required a vast array of land holdings that could feed Japanese ambition and cement its foothold in Asia as a formidable power. The Japanese were also involved in border skirmishes and disputes with the Soviet Union in the years leading up to the Second World War. A set of treaties during Germany’s invasion of Poland secured Soviet neutrality, which also allowed the USSR to invade Poland while being reassured of Japanese non-aggression.
Allied powers like the United Kingdom benefited considerably following the First World War. Alongside allies like France, the UK succeeded in orchestrating the dissolution of the Ottoman Empire and gained considerable territorial holdings in the Middle East based on spheres of influence. This collapse of the mighty Turkish empire resulted in permanent repercussions for the world at large, birthing numerous present-day nation-states. The United Kingdom, at the time, was the undisputed global power and sought to maintain supremacy by any means necessary. On the other hand, France took a more defensive approach and relied on treaties like those made at Versailles. Whereas, its occupation of the Rhineland region of Germany was to ensure it could keep German aggression in check. This approach would eventually become the very reason why France fell rather early in the war to come.
The United Kingdom also followed an approach now known as appeasement, preceding World War II. Throughout the 1930s, Nazism and aggressive ultranationalism grew insidiously in Germany. While leaders knew that Hitler had expansionist plans, the United Kingdom willfully let the German state expand unchecked despite their remilitarization of Rhineland. The German invasion of Austria also went unchecked. The UK, under then Prime Minister Neville Chamberlain, did not respond to any of these alarming events under the pretext of avoiding war. These acts of appeasement before the Second World War would result in aggressive German expansion that would conquer vast swathes of Europe following the commencement of conflict.
The dawn of the Russian Revolution in 1917 prompted the nation’s abrupt exit from the Entente bloc during World War I. By the time of the second global conflict, Russia had transitioned from a Czarist monarchy to a totalitarian communist state—the United Soviet Socialist Republics (USSR). The USSR initially signed the Molotov-Ribbentrop Pact with Nazi Germany, which ensured non-aggression from either side. The two states also divided Poland into two spheres of influence, which allowed for the sandwiched nation’s invasion by both Nazi Germany and the USSR in quick succession. The Soviet Union, however, would abandon the pact in the wake of Nazi Germany’s invasion in June 1941, following the commencement of Operation Barbarossa. This would ensure the placement of the USSR in the Allied camp, turning the tide in their favor despite heavy setbacks in the initial stages.
Across the Atlantic in the United States, a different set of political and economic forces dominated the nation, which was a late entrant into World War I and joined on the Entente side. Following the First World War, isolationist sentiments garnered steam, and the Great Depression continued for a significant portion of the ensuing decade. While the US had assisted nations like Germany financially, it eventually aided the Allies following the breakout of the Second World War in Europe. The unique approach served to assist democracies against totalitarian states through the Lend-Lease Act without impacting its neutrality in the conflict. However, this changed with Japan’s assault on Pearl Harbor in December 1941, following which the US joined the war on the Allied front.