KUALA LUMPUR – The ruling by the Permanent Court of Arbitration in The Hague against China’s territorial claims in the South China Sea is a watershed moment for international law and an unmistakable warning to China about its strategic assertiveness in Southeast Asia. China says that it does not recognize the PCA ruling; but that doesn’t mean it is undisturbed by it.

The question now is how China will respond. Will it change its often-aggressive behavior in the region, or will it continue to view the South China Sea mainly in terms of US-China competition? If China assumes that a war-weary and risk-averse US will avoid conflict, it could simply assert its South China Sea claims by force.

But belligerence could backfire in several ways. First, it would force the members of the Association of Southeast Asian Nations (ASEAN) to choose between China and the US, a decision that all of them would prefer to avoid. Whereas ASEAN member states – particularly the Philippines, Singapore, Thailand, and Indonesia – generally have deep military ties with the US, they also value their economic ties with China. The reality is that ASEAN states could choose to become independent players, rather than pawns in the US-China competition, implying that it is in China’s interest to maintain ambiguity in US-ASEAN relations.

Second, by militarizing outcroppings and artificial islands in the South China Sea, China is unwittingly strengthening ultra-nationalist groups in the ASEAN states. This development forces moderate leaders in these countries to adopt a tougher stance toward China than they otherwise would, in order to preempt attacks from the ultra-right and assuage their generals. A case in point is Indonesian President Joko Widodo’s recent visit to the Natuna Islands on a warship, a show of force in response to incursions there by Chinese fishermen and navy vessels.

China must know that the material advantages from closer ASEAN-China economic relations will not be enough to guarantee smooth diplomatic relations. Most ASEAN member states are middle-income countries with educated elites who hold diverse views. And even extremely poor and politically illiberal Myanmar has reduced its dependence on China in response to active wooing by the US.

China should rethink its insistence that negotiations over its territorial claims could be conducted only with individual ASEAN states, and not with ASEAN as a bloc – a stance that creates the impression that China is committed to bringing about the group’s breakup. But China should not encourage ASEAN’s demise, because that would drive several now-neutral ASEAN states further toward the US. Moreover, because ASEAN must represent ten countries with one voice, and must reach a consensus before it speaks, China has little reason to fear that a common ASEAN negotiating position would be totally unacceptable – particularly given recent history.

For example, a 2012 meeting of ASEAN foreign ministers failed to produce a joint statement, because Cambodia, a Chinese ally, would not agree to mentioning the South China Sea. And in a meeting of the same group in Kunming, China, in June 2016, ASEAN had to withdraw a joint statement critical of China’s actions in the South China Sea when China, again, pressured Cambodia, as well as Laos, to object.

What this shows is that, in dealing with ASEAN, China gets to negotiate twice – first, through its closest allies within ASEAN in the formulation of common ASEAN positions, and then directly with an ASEAN team that could include one of its allies. Certain ASEAN countries clearly value their relationships with China more than their relationships with other ASEAN countries; so, unless China has already ruled out any negotiation on the South China Sea, it should not rule out meeting ASEAN as a bloc.

The irony in China’s South China Sea claim is that the Communist Party has fallen into a trap set unintentionally by the Kuomintang, which it defeated in 1949. It was the crumbling Kuomintang that in 1947 drew and promulgated the original “11-dash line” map – subsequently reduced to nine dashes by Mao Zedong, in a fraternal gesture to Vietnam – in a futile effort to rally the population to its side via imperial ambition.

There is no need for the winner of China’s civil war to follow the path of the loser. And if China has to press this claim in order to appease ultra-nationalist elements, it should do so by deploying diplomats, rather than its military.

Of course, a win-win outcome from The Hague decision will also depend on ASEAN and US actions. ASEAN and the US are highly skeptical of China’s repeated public promises of a non-hegemonic mode of international relations; but they should not be blind to China’s legitimate security concerns, which it will never neglect. Both ASEAN and China must now exercise self-restraint and start negotiating in good faith to resolve the territorial disputes in the South China Sea in a way that addresses these concerns.