After the expiration of the treaty in 1979, Deng Xiaoping wanted China not to negotiate with the Soviets unless they agreed to China's demands such withdrawing from Afghanistan, removing their troops from Mongolia and the Sino-Soviet border, and ceasing their support of the Vietnamese invasion of Cambodia. The expiration of the treaty allowed China to attack Vietnam, a Soviet ally, in the Third Indochina War as a response to Vietnam's invasion of Cambodia since the treaty had prevented China from attacking Soviet allies.