AS in any human relationship, the ties between two ostensibly friendly nations can blow hot and cold.

Over the past month, the vinegary mood between Cambodia and Thailand has turned sweet and chummy.

Yet little has changed aside from former Thai prime minister Thaksin quitting his sinecure as economic adviser to Cambodia. All other irritants remain.

Still, a mood of childish petulance has given way to one of sober maturity, and for that we must be thankful.

In contrast, ties between the region’s major Muslim nations, Indonesia and Malaysia, have soured after seven Johor fishermen strayed into Indonesian waters and were detained.

In a fit of impulsive vengeance, Malaysia arrested three Indonesian maritime officers.

All were later released, but anti-Malaysia sentiment persists in Jakarta. “We are running out of patience with these street protests against us in Indonesia,” Foreign Minister Anifah Aman said.

It will blow over soon, and in any case, bilateral ties are less important than those between ASEAN members and the global superpowers, China and the United States.

Recently, these big guys have been jostling for the affection of Indonesia, which, with 240 million people, is the world’s third-largest democracy and most populous Muslim-majority nation.

Both superpowers want to boost trade, investment, and most recently, military cooperation with this strategically positioned, resource-rich nation that anchors ASEAN.

Beijing nosed ahead in the race when it signed the Indonesia-China Strategic Partnership designed to expand political, cultural and military ties.

That caused a tinkle of alarm in Washington that became a cacophony when the Indonesia-China Defence Security Consultation talks began and Jakarta hosted two Chinese warships.

But then, almost as suddenly as it had begun, China’s charm offensive stalled – in part because of Washington’s belated but robust efforts to elevate ties with Indonesia.

Those efforts have accelerated remarkably this year, starting in March when an American technical team jetted in to check out the Indonesian Air Force’s US-built aircraft, and then in June, when a US-Indonesia defence integration accord was signed.

Just over a month ago, Jakarta requested – and will get – additional US military equipment, including F-16 fighters and C-130 Hercules aircraft.

Most significantly, Washington said it will lift a ban on cooperating with Kopassus, Indonesia’s controversial special forces unit that has been linked to atrocities in East Timor, Aceh and Papua.

The US clearly wants to elbow out Beijing and become the key military supplier to Indonesia – just as it is doing for Vietnam and has long been for Singapore, Thailand and the Philippines.

The message is blunt. Uncle Sam to Red Dragon: There is room for only one sheriff in Southeast Asia and it’s us.

However, even the best laid schemes can go astray, and all the good work has been jeopardised by President Barack Obama’s on-again, off-again plan to visit Indonesia.

Obama was going there last November after attending the APEC Summit in Singapore, but he reneged – and had to call Indonesian President Susilo Bambang Yudhoyono to apologise.

Then he pulled a dramatic double cancellation in March when he was needed stateside to prevent his healthcare reform bill from derailing in congress.

That was followed by a fourth kiss-off in June when he stayed home to assert leadership in plugging the oil-spewing hole in the Gulf of Mexico.

Apparently, he may now visit Jakarta in November, although in that month he will go to Seoul (G-20), Yokohama (APEC), and India, so don’t bet the house that he’ll include Indonesia.

These serial cancellations have unnerved Southeast Asia and have especially upset Jakarta, which seeks to “row between two reefs” by maintaining balanced ties with both the US and China.

But now the US is blowing hot and cold at the same time – and that’s decidedly not nice. Obama should get his act together and get on a plane to Jakarta as soon as possible.