VCP used CCP to help them liberating Northern Vietnam from France, then US. Originally, this is a good chance for China and Vietnam to build trustworthy relationship. However, along with victory of VCP, their leadership go retarded to play the classical "befriend far and attack near" Chinese strategy, USSR was a superpower back then, so VCP strengthened their relationship with USSR to confront China since China and USSR was in de factor confrontation after 1960 esp after their Uncle Hu died. Their leadership lost foundamental rationism and invaded Cambodia to persue their wet dream of Great Indochina, and expected that USSR would attack China if China interfered. Vietnam lost the opportunity which occur only once in the past 1000 years. Lê Duẩn should be responsible for this tragedy. China will never trust Vietnam again in foreseeable future. This imply how important it is for a nation to cultivate a good leadership team. This is probably fate of Vietnam.