Ever since Beijing lodged its nine-dash line with the United Nations five years ago, the countries that live around the South China Sea have been on a diplomatic roller-coaster, with the Philippines and Vietnam leading attempts to counter China’s reassertion of ancient claims.

Ancient claims have no standing in international law, hence China has relied on its military muscle in trying to force other parties – that includes Indonesia, Malaysia and Brunei – into negotiating on a bilateral basis.

That option is an anathema in Hanoi and Manila, where frustrated officials want negotiations to be handled on a multilateral level through the Association of Southeast Asian Nations (ASEAN).

But ASEAN is far from united, even among countries whose territorial integrity has also been challenged by Beijing's claim over 90 per cent of the South China Sea, reaching deep inside the 200 nautical mile limit that defines each nation's Exclusive Economic Zone (EEZ).

In Cambodia, which is not directly involved in the dispute, the two main political parties have backed Chinese claims. But the realities are slightly more complicated given Prime Minister’s Hun Sen’s tight relationship with the Vietnamese. Cambodia’s dependence on Chinese aid and investment – worth more than $11 billion during the last two decades – had Phnom Penh backing Beijing. This caused a split within ASEAN while Cambodia held the chair in 2012, a major embarrassment for the trading bloc and its 10 members.

Equally, opposition leader Sam Rainsy has also said his Cambodia National Rescue Party (CNRP) would back Beijing’s maritime claims but he has not explained his reasoning. His deputy Kem Sokha has since contradicted Rainsy’s Beijing pledge.

Analysts have also noted the CNRP does not hold regular party meetings in the traditional sense, where policy is put forward for approval. Instead it tends to write policy on the run and it has also pushed a nationalistic agenda that plays on anti-Vietnamese sentiment.

“It’s a shabby way of doing business and making deals but that’s the reality of Cambodian politics,” one analyst, who declined to be named, said. “If, and it’s a big if, they ever win government, seeing whether they can actually govern and formulate a coherent foreign policy will become something of a national sport.”

In Malaysia, attitudes are similar and appeasement of China is nothing new. The Beijing leadership is persistently annoyed by laws that favour indigenous Malays over ethnic Chinese in Malaysian life. Relations were also tested by the disappearance of Malaysian Airlines flight MH370 with 239 people on board, mostly Chinese. Fears of unnecessarily antagonising the big neighbour to the north are paramount. Carl Thayer, Emeritus Professor at the University of New South Wales, said Malaysian Prime Minister Najib Razak held a tight reign over such issues, suppressing any attempt to publicise maritime incidents in the South China Sea. “Malaysia delivers its protest through diplomatic channels,” he said.

That stands in sharp contrast to the brash tactics deployed by China and Vietnam around the Paracel Islands and the Philippines in the Spratlys. Malaysia’s softly, softly approach has enabled it to start developing oil and gas blocks at James Shoal while remaining aloof from ASEAN.

“Malaysia has taken a relatively low key role in public on the two occasions Chinese warships have passed by James Shoal to claim it as part of China’s territory,” said Thayer. “Malaysia has been concerned over these visits, as well as concerned about the types of pressure China has exerted against the Philippines and Vietnam.”

James Shoal sits just 80 kilometres off the West Malaysian coast and 1,800km south of China. Yet, Beijing has argued, what it calls Zengmu Reef, which also lies 22 metres underwater, is the most southern part of China.

Prospects of a united ASEAN front on the maritime dispute, which some policy wonks in Washington have said is potentially more dangerous than conflicts in the Middle East, have not been helped by politics elsewhere in the region.

Brunei is following the Malaysian lead after being internationally rebuked for introducing Sharia law. In Thailand, the coup d’etat appears to have ended Bangkok’s role as chair in formulating a coherent ASEAN policy on the issue.

The great unknown is Indonesia. Beijing’s claims in its waters were deliberately obscured until Jakarta sought clarifications from visiting Chinese generals earlier this year.

They confirmed China was claiming the Natuna Sea, angering Indonesia but pending elections, held last week, put on hold any diplomatic comeback by out-going president Susilo Bambang Yudhoyono. Those claims are also perilously close to Singapore.

If Kuala Lumpur feels its $62bn worth of annual trade ties are being jeopardised by Vietnamese and Filipino actions in the South China Sea then it might go it alone and negotiate with China on a bilateral basis.

Cambodia could follow suit and that would further undermine ASEAN unity and give Beijing what it wants most – a dysfunctional trading bloc incapable of negotiating for itself.

Luke Hunt is a journalist based in Phnom Penh, covering Southeast Asia