Conflict in the South China Sea is not new. In the dog days of the Vietnam War in 1974, China took advantage of the conflict between North Vietnam and the weakened South Vietnamese regime to seize the Paracel islands.

Curiously in the sharp war between China and Vietnam in 1979, triggered by Vietnam's overthrow of the Khmer Rouge in Cambodia, there were no naval engagements.

Almost a decade later in 1988 there was a clash between the Chinese and Vietnamese in the Spratly Islands resulting in substantial loss of life.

The conflict may be long running, but there are several reasons why it has become much more dangerous. There can be little doubt that President Obama in his second term will find the South China Sea one of the hottest issues in East Asia.

First, although there are four Association of Southeast Asian Nations states that lay claim to the Spratlys -- Vietnam, the Philippines, Malaysia and Brunei -- historically this has largely been a bilateral dispute between China and Vietnam. It has now become very different, pitting almost all of ASEAN's members against China. This became clear in July when for the first time in the 45-year history of the organization, an ASEAN foreign ministers meeting in Phnom Penh ended without a formal communique.

The cause was a failure among its ten members to agree on a common stance to the South China Sea and China's growing maritime assertiveness. For its part, the United States has underlined the enormous importance it attaches to freedom of the seas and, of course, the South China Sea, through which two thirds of the world's trade is estimated to pass.

Secondly, the Phnom Penh meeting confirmed ASEAN countries in their att-empts to enhance their military and especially naval capabilities. A striking development has been the rush to acquire submarines. Indonesia intends to buy a dozen by 2024. A deal to purchase the first three with South Korea was signed in December 2011. Malaysia is buying submarines from a Franco-Spanish consortium and Vietnam is acquiring six Kilo class vessels from Russia. Singapore has already purchased Swedish-built submarines. For its part Thailand is planning to buy six former German submarines and, budget permitting, the Philippines has announced its intention to do so as well. There is now a maritime arms race with the added danger that none of these countries has experience in the operation of submarines.

Thirdly, there appears evidence of growing anti-Chinese sentiment throughout the region. An interesting case is Singapore where the death of two Singaporeans in a crash involving a Ferrari driven by a Chinese national prompted an extraordinary outburst against the Chinese on the internet. Inevitably, in the Philippines and Vietnam, there have been anti- Chinese demonstrations after Chinese incursions into their waters.

While Indonesia, the largest country in the region, has no claims on the Spratlys, it is concerned at China's growing assertiveness. It has a long history of hostile sentiment towards China.

Fourthly, there is growing US concern about Chinese behaviour, and this is not limited to the South China Sea. Washington is equally troubled by Beijing's antipathy towards Japan over the disputed Senkaku/Diaoyu Islands. For Washington there are now too many players involved and the competing sovereign claims are not susceptible to resolution in the foreseeable future. The inescapable conclusion is rising tension. China's leadership changes may not be helpful, making new incumbents less likely to compromise.

Fifthly, there are economic imperatives among all the claimants to the South China Sea driving them in a more assertive direction. All are anxious to pursue oil and gas exploration while protecting their claimed fishing ground as coastal waters become depleted. Fishing vessels from all countries are pushing further into disputed areas. In addition, among all claimants there are growing domestic lobbies fired by the fear that their country is being excluded from maritime assets.

These domestic economic and political imperatives are undermining the longstanding restraints on conflict. The new administration of Xi Jinping and Li Keqiang will need some time to settle in, but time is in short supply. ASEAN discussions on a code of conduct for the South China Sea appear to be exhausted after the Phnom Penh debacle.

The International Crisis Group has suggested that a troika of ASEAN foreign ministers could engage in shuttle diplomacy between the claimants to the islands. But what of the interests of non-claimant members in ASEAN, or for that matter the United States? Michael Wesley of the Lowy Institute in Sydney has argued that Australia is well placed to broker a solution. But why would a new Chinese leadership want to see a close US ally play such a role?

My view is that we should look to the United Nations, and in particular the Secretary General's good offices, to prevent the dispute from escalating. In this case, he should take the initiative of appointing a Special Representative

Michael Williams is a Distinguished Visiting Fellow and Acting Head of the Asia Programme, Chatham House

(c) 2012 Distributed by Tribune Media Services