Ever more diverging Chinese and Soviet strategic and political doctrines had increased Cause_change_of_position_on_a_scale the Sino-Soviet split of the mid-1950s .

The Sino-Soviet split re-emerged Coming_to_be following the lull during the Vietnam War and conflict between North Vietnam and its Cambodian allies in the Royal Government of the National Union of Kampuchea , and the newly-formed Democratic Kampuchea begun Process_start almost immediately in a series of border raids by the Khmer Rouge that erupted into the Cambodian–Vietnamese War , with Chinese forces directly invading in the Sino-Vietnamese War and subsequent border conflicts .