As many analysts have cautioned, Thailand has swung closer to China's orbit since the junta took control in May 2014. This wasn't Nostradamus-level foresight. The US was always going to have a tough time publicly maintaining relations with a military government, particularly with so much riding on Myanmar's democratic transition next door (ie. Hillary Clinton's presidential campaign).

The depth of ties between the US and Thailand, Washington's closest and oldest ally in the region, has made it difficult to take a step back. The knowledge that Beijing would happily pick up the slack left by any weakening of US-Thai relations complicated things further. But as we approach a year since the military seized power, and with no elections in sight this year, the US has upped the rhetoric in the past month to serious effect.

Last month, the US Charge d'Affaires in Bangkok, Patrick Murphy, said in a speech that Thailand should lift the martial law that has been in place since May 2014, adding that the trial of former prime minister Yingluck Shinawatra was 'politically driven'. Bangkok wasn't impressed. The head of the military government, Prayuth Chan-Ocha, rebuked Murphy, explaining that 'Thai democracy will never die, because I'm a soldier with a democratic heart. I have taken over the power because I want democracy to live on.' Bangkok summoned Washington's top diplomat in East Asia to caution that the US should stay out of Thai politics. As Murphy noted this week, US-Thailand relations are going through 'challenging' times.

That euphemism was further highlighted in the past week, when the US followed through with its October promise of a scaled-down version of its annual joint military exercise. Cobra Gold, which began yesterday, is (usually) the world's largest annual multinational military exercise. This year it is smaller. Washington cut the number of troops it sent compared to lat year by nearly a quarter, to 3600. It stopped short of scrapping the event altogether, as this would have had wide-ranging implications across the region. 

Bangkok then played some strong-arm diplomacy of its own. On Friday, during a two-day visit by China's Defence Minister, Chang Wanquan, China and Thailand agreed to boost military ties over the next five years. The agreement includes, among other things, intelligence sharing, cooperation on transnational crime, and increased joint military exercises. 

This US-Thailand-China interplay could further hurt Southeast Asian views of the US 'pivot'. Many in the region will be watching how both the US military and Thai military respond in coming weeks. Any further unstitching of the relationship could unravel confidence in the pivot in Southeast Asia. That could encourage Beijing to boost military-to-military ties with willing Southeast Asian states.