On December 15th, 1978, Vietnam launched a blitzkrieg invasion of Cambodia to defend their land and force Cambodian Prime Minister Pol Pot's Khmers Rouge regime from its seat of power. Two million Cambodians had died at the hands of the Khmers Rouge regime, which had repeatedly crossed the border to massacre Vietnamese civilians and torch villages. In Vietnam, the war is known as a counter-offensive on the Southwestern border, whereas Cambodian nationalists perceive it as a Vietnamese invasion.

Once the Vietnamese had forcibly removed Pol Pot's regime, the ensuing war sparked a decade's worth of international tension during the Cold War. The Vietnamese finally withdrew in September 1989, but not without losing approximately 30,000 of their soldiers.