Write any one causes of unsuccessness of League of Nation.

One major cause of the League of Nations' failure was its lack of universal membership. The absence of the United States—a key economic and military power—from the outset weakened its authority. The League relied on collective security, but without major powers like the USA, its ability to enforce decisions was severely limited. Additionally, the Soviet Union was excluded until 1934, further reducing its global influence. This structural flaw made it difficult to address global conflicts effectively, as critical powers could ignore or undermine its resolutions. The League’s inability to act decisively in crises like Japan’s invasion of Manchuria (1931) and Italy’s invasion of Ethiopia (1935) highlighted this fundamental weakness.