The primary cause of the French-Indochina War was the struggle for independence from colonial rule. After World War II, Vietnamese nationalists, primarily led by the Viet Minh under Ho Chi Minh, sought to end French colonial control over Indochina. The conflict escalated in 1946 when the French attempted to reassert their authority. The war, deeply intertwined with issues of nationalism and self-determination, was characterized by guerrilla warfare and significant casualties on both sides. Ultimately, it culminated in the decisive battle of Dien Bien Phu in 1954, leading to the Geneva Accords and the partition of Vietnam.