Vietnam has been remarkably successful in getting the South China Sea issue back onto the international agenda, in the process underscoring its new ties with the United States and asserting Hanoi's leadership of Asean on this issue.

China is furious but its reaction, seemingly driven by President Hu and the People's Liberation Army rather than the foreign ministry in strongly re-asserting China's claims to the whole sea, has brought further attention to the issue. It is being watched closely by Japan, and Russia and India are continuing to strengthen their relations with Vietnam partly with the sea issue and navigation rights in mind.

However, the Southeast Asian countries in dispute with China would be in a very much stronger position to confront China's claims if they were able to resolve their own conflicting claims or at least engage in the joint exploitation to which they are in theory pledged. There is scant sign to date that they are going in that direction.

Essentially there are two rather separate issues in the dispute. The first, which involves only the littoral countries China, Vietnam, the Philippines, Malaysia and Brunei (for these purposes Taiwan's claims are the same as China's).

The second is about freedom of navigation. That involves all major nations for whom the waterway is crucial for their shipping, including nearby countries like Indonesia as well as Japan, the US, etc. As China claims dominion over the entire sea as well as its various islands and rocks, acceptance of its claim would turn the sea into a Chinese lake to which others could only have access with China's consent even though China and Taiwan between them own only about 20 the sea's coastline.

Indonesia additionally has a separate issue. Although China's claims do not impinge on any of its land waters, they come so close to the Natuna gas field that issues of ownership of gas deposits could become disputed, as well as seabed rights to the northeast of the Natuna field.

Offshore oil and gas is important for the Southeast Asian states but much less so for China, for whom the region's reserves are assumed to be relatively small compared to its needs. Likewise fishing is of some interest to all the nations but over-fishing means this is less and less significant. China's over-riding interest is strategic.

Of the various disputed groups, the Paracels, which lie due east of Danang, are only claimed by Vietnam and China – which forcibly occupied them in the dying days of the South Vietnam regime. Only China and the Philippines dispute the Scarborough shoal and Macclesfield bank.

It is the Spratly group which is the main bone of contention, with all claimants overlapping and where the non-Chinese ones need to find some common ground. Vietnam claims all the Spratlys by right of historical occupation even though most of them lie closer to the Philippine and Malaysian coasts.(China's claims are similarly based on history, real or imagined) The Philippines claims most but not all on a mixture of principles – the archipelago principle, continental shelf, and occupation of empty territory. The Malaysian and Brunei claims are based on the continental shelf principle – the islands lie in seabed of less than 200 meters in depth extending from their coastline.

As of now Vietnam has a presence on about 20, China about nine, the Philippines about eight, Malaysia three and Taiwan just on1 of the islands, rocks and shoals. With such conflicting bases for their claims, as well as the claims themselves, it will be extraordinarily difficult for the non-Chinese nations to get together. Nationalist sentiment runs against abandoning any claims. Seemingly meaningless rocks become national symbols. Nor does it seem likely that they would agree to submit to international arbitration rulings in the way that Malaysia settled disputes with Indonesia and Singapore.

But they could surely agree – and in this be joined by Indonesia and maybe Singapore – in asserting both freedom of navigation and the principle that claims to specific islands do not include claims to 200-mile economic zones.

The navigation issue is doubly important because the main shipping channels, through which pass a major portion of global sea trade -- run to the north of the Spratlys, an area of widely varying depths and many shoals. The islands themselves are of economic value and only the continental shelves appear to offer oil and gas prospects.

On the question of history the non-Chinese could also form a common front – at least if they were better informed about their pre-colonial pasts. Vietnam's claims are based on Vietnamese imperial records. But a much earlier claim can be made for the Cham empire, based in what is now central Vietnam. The Cham were a Hinduized, Austronesian (same language family as Malay, Tagalog etc) -speaking people who ran much of the trade in the south China sea until the 15th century. Vietnam may be reluctant to make a claim based on a nation it wiped out, but there is abundant evidence of trading across the southern and central part of this sea long before the Chinese became involved.

Indeed despite the name given to it by westerners and then translated into Malay and Tagalog, the South China Sea is more a Malay than a Chinese sea. In the days of the Cham empire it was known as the Cham Sea. Seafarers from Borneo ran the spice trade with China while those from Sumatra (the Sri Vijayan empire and others) the shipping that brought Chinese Buddhist pilgrims to India and Sri Lanka, and reached the coasts of Africa a thousand years before China's Admiral Zheng He during the Ming dynasty.

Indeed, if the Asean claimants were to start with a joint study of their history trading and fishing across the sea, they might have a better grasp of where their interests now lie.