Except, D.C., that 1979 border war between China/Vietnam was due to Vietnamese leadership refusing to pay back huge loans from money, resources, and arms the Chinese felt they were owed and what they'd given them during their long conflict with the U.S for well over a decade in trying to reunify the country. Vietnam refused, and also it was done because Vietnam had invaded and deposed Chinese ally Khmer Rouge's brutal, genocidal regime in Cambodia which gave us the " Killing Fields".