LAST week, Indonesia took over from Vietnam as chairman of the Association of Southeast Asian Nations.

Okay, yawn, yawn, you might think, but please don’t. Because unlike most news items about ASEAN that are soporific enough to put a hive of killer bees to sleep, this one is sexy and significant.

To begin with, strictly speaking, Indonesia had no right to assume the chair, which is rotated every year in alphabetical order among the group’s ten members.

After Vietnam stepped down at the end of 2010, Brunei should have taken over.

However, as members of the association know, as does the rest of the Asia Pacific region, the tiny sultanate carries little clout in strategic political terms.

Still, clout or not, ASEAN has never before deviated from the strict alphabetical rotation – until this year, when its members decided they needed a heavyweight in the chair who packed a solid punch and was prepared to wield it.

That meant there was only one contender: Indonesia.

The reason is obvious: over the past couple of years, China has been ravenous in seeking to devour the sovereignty claims of ASEAN members to their offshore islands and territorial waters.

Outlined in red on its hegemonic maps, China’s frontier snakes down the Philippine coast, hugs the outline of Sabah, Brunei and Sarawak, cuts up close to peninsular Malaysia’s beaches and then shoots north following the contour of Vietnam.

It encircles the entire South China Sea, leaving nothing for the poor little ASEAN claimants – Brunei, Malaysia, the Philippines and Vietnam.

And China has explicitly stated that in dealing with any disputes, it will only do so with individual claimants, not with ASEAN as a group.

Easier to gobble them up one by one, you see.

Recently, it has been doing just that – occupying islands, detaining fishing boats that enter “its” waters, scaring off oil companies hired by ASEAN members to develop offshore fields.

In a recent move that finally forced ASEAN to act, it called the South China Sea a “core issue” on a par with Taiwan, Xinjiang and Tibet.

That led to a growing sense that Beijing has effectively erased the first word in its much touted “charm offensive” towards the region.

Consequently, ASEAN turned to its traditional powerhouse of Indonesia to show the way. And when Jakarta agreed to take up the mantle and become chairman out of sequence, there were great inhalations of relief.

As the group’s Secretary-General Surin Pitsuwan said: “Indonesia has a weight, an international legitimacy and a global appeal to draw tremendous support and attention.”

He is right. As he was when he added: “The swap was done with real necessity.”

That was echoed by Indonesia’s ASEAN Ambassador Ngurah Swajaya, who said that to “promote regional dynamic equilibrium” it was essential for the group to be the driving force in the evolution of the area’s architecture.

That word ‘equilibrium’ signalled to Beijing: You must give and take, not just take.

Ngurah went on to say that promoting a united ASEAN-led regional architecture required the group to speak with a collective voice.

Translation: United we stand, divided we fall.

Of course, even standing together with powerful Indonesia at the helm, ASEAN will still need help to face down the red bear.

Thankfully, Washington has stepped in.

At last year’s ASEAN Regional Forum, United States Secretary of State Hillary Clinton asserted that “freedom of navigation, open access to Asia’s maritime commons and respect for international law in the South China Sea” were in America’s “national interest.”

Beijing was furious, but ASEAN members were visibly revitalised.

They know, as former Australian PM Kevin Rudd said last year, that China can only succeed in its audacious land grab if America cedes the field.

And with an Indonesian-led ASEAN at its back, Uncle Sam appears unlikely to do that for the forseeable.