President Barack Obama attends a farewell dinner with Southeast Asian leaders Wednesday, capping eight years of careful courtship that has created new friends, but left links frayed with America's oldest regional ally -- Thailand.
When Obama looks around the gala dinner table in Vientiane, he will find a bevy of new partners.
His engagement with former Communist foes in Vietnam and now Laos is slowly easing the bloody burden of history, in much the same way as his opening to Cuba.
More striking still will be the presence of Myanmar's de facto leader Aung San Suu Kyi, who spent much of the last three decades held prisoner by a brutal military junta.
Obama's engagement with Myanmar -- a country he has twice visited -- has butressed a political transformation, helping convince the generals to share power with Suu Kyi's democratically elected government.
"Just sitting back and criticizing countries has a limit in terms of what it can achieve," said Ben Rhodes, an Obama aide who has worked closely on the US' policy to Myanmar.
Where George W. Bush routinely skipped meetings with Southeast Asian heads of state, Obama -- perhaps unsurprisingly for someone who spent a chunk of his childhood in Indonesia -- has been a regular visitor.
- Bouquets and brickbats –
But the trips have not all been plain sailing, as Obama was reminded this week when he was labelled a "son of a whore" by firebrand Philippine leader Rodrigo Duterte.
Yet experts say it is Thailand that represents the starkest failure to leverage US diplomatic power in the region.
Two military coups in quick succession have damaged relations with Bangkok, a treaty ally and regional powerhouse whose relations with Washington date back more than 180 years.
The US has not been able to prod the generals into restoring elections or easing controls on dissent.
Notoriously prickly junta leader, Prayut Chan-O-Cha, has also frequently bristled at US criticism of the darkening human rights environment in his country.
Even the smallest diplomatic slight, perceived or imagined, has the ability to sour relations further.
When Prime Minister Prayut talked to Obama on the margins of the US-ASEAN summit in Sunnylands, California, this year, US and Thai sources said the junta leader felt bridges were being rebuilt following the coup.
But on landing in Bangkok he was furious when told a mid-level State Department official had publicly berated his government's human rights record.
A Thai official told AFP that public opinion in his country could ultimately swing against the United States.
For their part, US officials point out that Thailand's latest coup left Washington with little room to manoeuvre.
"We did the bare minimum we had to do under the law," said one former Obama official, referencing a near $5 million cut in military aid immediately after the last coup in 2014.
But the US has not scrapped wider military co-operation, including annual war games held by the kingdom.
Still, some American officials worry that Thailand is being pushed too far towards its powerhouse neighbour China.
That could be particularly damaging given the context of a "once in a century reordering of political and economic power in Thailand," driven by a looming royal succession, according to Ernest Bower, a Southeast Asia expert at the Center for Strategic and International Studies.
With army power entrenched by a new constitution, the military are set to be a key player in the new political order.
The Thai military used to be "partnered almost exclusively with the United States and that is changing," said Des Walton, a former defenseattache in Bangkok.
"They are expanding relations notably with China and Russia," he said. "At face value I don't see how that is consistent with US interests."
- Too late for Obama –
Thailand remains strategically pivotal to US regional interests.
"If you go from Korea all the way down to Thailand there is a huge swath which is basically all China, where the United States doesn't have access to mainland Asia. Thailand is it," he added.
But fears Thai public opinion could swing against the United States, may be premature.
While royalist conservatives hiss at any US condemnation of the junta, wider trade, education and diplomacy links remain strong.
Beijing does not criticise the junta, but it has so far failed to deliver on several gilded promises of support for major infrastructure projects.
Some in Washington believe that provides an opportunity for rapprochement.
But it may be too late for Obama.
"I think only presidential intervention would make a difference and that is not going to happen with the Obama administration," said Bower.
The White House says another pull-aside meeting with Prayut is unlikely to take place in Laos, even if they are in the same dining room together.