Well we have to understand the geopolitik of the region and also apply his role in context to Cambodia's strategic importance. And that is : a regional pawn. Cambodia is a tiny shrimp between two great whales: Thailand (Siam) and Vietnam. Always has this been the geostrategic reality for almost a millenia now. Cambodia's feigning friendship with China is strategic posturation by the Cambodians as to try to balance the regional equation wherein it is involved -- its a security nature to try to balance the Vietnamese threat, which is very much true for Cambodia since Cambodia's 15 million can be easily subsumed by Vietnam (98 million and growing). In fact, Vietnam's population is more than Thailand + Laos + Cambodia. So let that be contextual framework in intra-regional comparitive analysis.
In the end we know that the master of Cambodian internal affairs for the past 50 years has been Vietnam. She has deposed the Khmer Rouge and mobilized 200,000 soldiers of the VPA to finish that mandate, consequetively fighting a northern skirmish with the Chinese in the 1979 Sino-Vietnam War. China's mandate in that war was to try to lift Vietnam's occupation of CPC-alligned Khmer Rouge, but that resulted in utter strategic and tactical failure because:
- Vietnam's paramilitary forces effectively bled the PLA and caused over 35,000 PLA casualties, resulted in PLA retreat less than 6 months into the campaign without realizing their strategic goals of forcing the VPA out of Cambodia.
- Cambodia was under Vietnamese control from 1978 till 1991. Even now, Vietnam still has massive security investment in Vietnam and the VPA maintains 15 divisions near the border with Cambodia. In case of any hostility, say Cambodia breaks into civil unrest, rest assured Vietnam will send in that 150,000 force into Cambodia to quell rebellion and restore civil law and order.
China , in essence, can only provide monetary and moral support. But real military support? No. Vietnam has been the master of Southeast Asian mainland affairs for the past 50 years. Even Thailand will not dare engage the Viets.