While global decolonization was already under way by the time World War II broke out, the devastation suffered by colonial powers during that war made their ability to sustain colonial holdings far from their capitals increasingly difficult. While France infamously attempted to reclaim its pre-war colonies in what had been called French Indochina, its ignominious defeat at the hands of the Viet Minh served to illuminate the extent of the former colonial powers’ weaknesses. Indeed, the United States also would learn the lesson that small less-developed countries with bountiful natural resources were not as weak as they might have seemed. The reason for that was the rise of the Union of Soviet Socialist Republics as a world power—a development that stemmed directly from World War II.
Following the Russian Revolutions of 1917, and despite its own vast colonial empire around its borders, Russia represented a political counterweight to the imperial powers of Western Europe. The incalculable effort sustained by Russia to push large, well-equipped and well-trained German armies from its land and all the way through Eastern and Central Europe resulted in the establishment of a new world power hostile to the old Western empires. The end of World War II resulted in the establishment of a new global structure that pitted East against West, with the Soviet Union considered a major military threat to those former colonial powers. With the political and military support of this new global power, existing and former colonies of the West had a new and powerful ally. Soviet (and Chinese) support to the North Vietnamese was instrumental in the latter’s ability to ultimately prevail over the American effort at preventing the subjugation of South Vietnam to the North.
As the Soviet Union grew in military and economic strength over subsequent decades, the ability of anti-colonial militias in Africa, especially in Angola and Mozambique, to fight European colonialism increased considerably. The economic devastation suffered by Great Britain and France during World War II left them too weak to sustain overseas empires. The rise of the Soviet Union meant less-developed countries occupied by former Western powers now had a powerful and determined ally. That is how World War II contributed to global decolonization.