What was the primary reason for the political instability in Germany post-World War I?

The primary reason for the political instability in Germany after World War I was the weakness of the Weimar Republic. Established in the aftermath of the war, the Weimar Republic faced enormous challenges that undermined its legitimacy and stability. These included widespread dissatisfaction with the Treaty of Versailles, which many Germans felt caused national humiliation and economic hardship. The republic was also established under a system that made it difficult to form stable governments, as it relied on proportional representation, leading to fragmented parliaments and frequent changes in leadership.

Additionally, the Weimar Republic was confronted by a range of extremist parties from both the left and right, such as the communists and the Nazis, both seeking to exploit its weaknesses. The republic's inability to address the significant economic crises, including hyperinflation in the early 1920s and the Great Depression towards the end of the decade, further eroded public confidence and made it difficult for any government to maintain order or effectively govern. This instability created a fertile ground for extremist ideologies, but it was the inherent structural weaknesses of the Weimar political system that were the root cause of its inability to stabilize the government.