Why western democracies stop this aggression of France Japan and Germany?

Western democracies did not stop the aggression of France, Japan, and Germany during World War II. Instead, they fought against these countries in order to stop their aggression and restore peace to the world. The United States, Great Britain, France, and the Soviet Union were the main Allied powers that fought against the Axis powers of Germany, Italy, and Japan. The war ended in 1945 with the defeat of the Axis powers and the establishment of the United Nations to prevent future wars.