Those with historical awareness of our region will remember that the Chinese supported Cambodia even during its Khmer Rouge/Pol Pot era when (Soviet-supported and already united) Vietnam invaded Cambodia to stop Khmer incursions into Vietnam. To this day, of course, Vietnam still holds grudges against China--especially over dominion over strategically important and potentially energy-rich countries in the South China Sea. In more recent years, China too has been a large investor in Cambodia.
At the ASEAN Regional Forum where ASEAN and its dialogue partners including China and the United States just met in Phnom Penh, the Cambodian hosts chose to ignore the wishes of their fellow Southeast Asian Nations so as to not offend China. It's the equivalent of the United States brushing off the security concerns of Canada to curry favour with, say, the European Union:
Southeast Asian nations have failed to reach agreement on a maritime dispute involving China, ending a foreign ministers' summit in disarray after Beijing appeared to split the 10 countries over the contentious issue. The Philippines said in a statement on Friday that it "deplores" the failure of the Association of Southeast Asian Nations (ASEAN) summit to address the worsening row, and criticized Cambodia in unusually strong language for its handling of the issue.One of the faces of power is being able to set the agenda, and certainly China demonstrated its increasing clout in Southeast Asia by effectively telling its ally to scuttle any mention of conflicts in the South China Sea (let alone discuss the matter substantively during the meetings). Still, you have to wonder if such tactics can last since other Southeast Asian nations less closely allied to China will be warier about offending their fellow nations when they get their turns as ASEAN's rotating chair.
China has been accused of using its heavy influence over summit chair Cambodia and several other ASEAN members to block regional-level discussions on the issue and attempts to agree a binding maritime Code of Conduct. The Philippines said it took "strong exception" to Cambodia's statement that the non-issuance of a communiqué was due to "bilateral conflict between some ASEAN member states and a neighboring country". It said it had only requested that the communiqué mention the recent standoff between Chinese and Philippine ships at the Scarborough Shoal, a horseshoe-shaped reef in waters that both countries claim. "The Chair has consistently opposed any mention of the Scarborough Shoal at all in the Joint Communiqué and today announced that a Joint Communiqué 'cannot be issued'," the Philippine statement said.
The failure to issue a joint statement marks a sharp deterioration in efforts to cool tensions following recent incidents of naval brinkmanship over the oil-rich waters. China, whose trade and investment ties with Cambodia have surged in recent years, has warned that "external forces" should not get involved in the dispute.
Moreover, China should be concerned with how smaller nations in the region view such heavy-handed tactics. While China is now the largest trading partner of ASEAN, you have to wonder if its economic charm offensive can always be separated from the menacing position it maintains in being unwilling to discuss the South China Sea matter in a concrete way. That is, China should not always insist on negotiating with individual claimants bilaterally, when power asymmetries are greatest. That even within their grouping--namely ASEAN--there are conflicting interests certainly doesn't help the likes of the Philippines and Vietnam. That said, you have to wonder about the consequences of these two courting a broader US presence in the region out of uncertainty over China. Further alignment with the US bolsters Chinese claims of unwelcome outside intervention, adding to historical distrust of America in security matters. Make no mistake: China views the US as a strategic rival and vice-versa despite all the happy talk about increasing economic cooperation.