Trump Takes Credit for Another Peace Deal: Cambodia-Thailand Edition

Experts and observers say that Trump’s involvement likely did hasten a ceasefire this summer. His intervention elevated this saliency of the Cambodia-Thailand crisis. And his leveraging of tariffs against two economies who were already desperate to avoid an escalating trade war with the United States likely did grease the way for both sides to sit down. U.S. officials have acknowledged that Malaysia’s prime minister led the mediation efforts, but Trump did follow through on his promise, and set tariffs at 19 percent for both Cambodia and Thailand, down from 36 percent.

“It’s hard to say that if Trump did not call on July 26 that something would have stopped,” said P. Mike Rattanasengchanh, International Affairs Fellow at the Council on Foreign Relations and associate professor of history at Midwestern State University. 

“The threat of tariffs did play a role,” Rattanasengchanh said. “But I think what it does more is build international awareness of it – and obviously that puts more pressure.”

What Caused the War Between Cambodia and Thailand?

The modern-day border conflict between Cambodia and Thailand goes back hundreds of years, to the decline of the Khmer Empire (ancestors of Cambodians) in the 1400s and the rise of Siam (modern-day Thailand), when key areas of the now-contested territory came under Siam’s control. That included important landmarks, like Preah Vihear, a Hindu temple built in the Dangrek Mountains during the height of Khmer rule. (Thais call the complex Phra Viharn, and over time it has gained significance with Buddhists, too.) 

🧵A detailed timeline on escalations in the lead-up to yesterday’s clashes between Thailand and Cambodia.
Much of the escalation seems to stem from Cambodia, with their troops fortifying many sectors before the May 28 clashes and surging strategic assets immediately after.
🗺️ -… pic.twitter.com/Ef1XePiZcF

— Nathan Ruser (@Nrg8000) July 25, 2025

When France arrived to the region in the late 19th century, it did what a lot of colonial powers did, which is make new maps. In 1907, France (which ruled Cambodia as a protectorate) drew a map that put Preah Vihear, along with other landmarks, on the Cambodian side of the line. Siam signed the treaty recognizing these boundaries, though with France as the stronger neighbor, Siam had limited ability to object or challenge the deal.

It also didn’t settle anything. The Thais (Siam became Thailand in 1939) seized borderlands during World War II, which France later got it back. Cambodia became independent in 1953, and soon after, Thailand again seized Preah Vihear. Cambodia accused Thailand of illegally occupying its territory and took the dispute to the International Court of Justice (ICJ). In 1962, the ICJ ruled in Cambodia’s favor, citing those old French maps. This verdict came down just as the region entered into a period of chaos: civil war and the brutal Khmer Rouge dictatorship in Cambodia and American Cold War interventionism in Vietnam, Cambodia, and Laos. That turned this border region into an “alarmingly lawless zone of guerilla activity, human trafficking, and smuggling,” writes William Hurst, a senior fellow at RUSI.

By the 1990s, the region stabilized, as did the relationship between Cambodia and Thailand. A personal bond developed between Thailand’s prime minister Thaksin Shinawatra and Cambodia’s (authoritarian) leader Hun Sen, which helped thaw tensions, for a time.

Thaksin was ousted by a military coup in 2006, which set off decades of political turmoil in Thailand that is still playing out today. Broadly, this upheaval centers around a jockeying between the military, Thailand’s monarchy, and the traditional ruling elites and democratic and populist leaders. Those power struggles help explain Thailand’s reaction when, in 2008, Cambodia sought to register the Preah Vihear temple as a UNESCO World Heritage Site. Thai nationalists seized on this, and that pressure forced Thai’s then-Prime Minister Samak Sundaravej to oppose Cambodia’s application. In turn, Hun Sen used Thai’s claims as a nationalist cry among the Cambodian public.

Tensions escalated after UNESCO approved Cambodia’s application in 2008, and both countries surged troops to the border zone. Flare ups of violence happened in the years leading up to 2011, when the crisis boiled over into a deadly confrontation. At least 15 people died and many thousands were displaced. Both sides accused the other of starting the conflict, though Cambodia and Thailand later reached a ceasefire. Thailand and Cambodia brought the issue back to the ICJ, which reaffirmed Cambodia’s claims to the Preah Vihear temple, but left vague other areas that Thailand and Cambodia contested, which left an uneasy and fragile stalemate at the border.

Tensions escalated again earlier this year. In May, a Cambodian soldier was killed in a border skirmish. Thai Prime Minister Paetongtarn Shinawatra urged calm and peace, but the Thai military amped up the rhetoric, including encouraging a public campaign for Thais to support the military, an apparent effort to undermine the prime minister’s de-escalation efforts.  

In early June, Paetongtarn and Cambodia’s Hun Sen tried to smooth things over in a call. (Hun Sen hand-picked his son, Hun Manet, to become Cambodia’s prime minister in 2023, but Hun Sen remains president of the party and Senate, and so is more or less still in charge.) Paetongtarn also just happens to be the daughter of Thailand’s former prime minister Thaksin, who, again, had a good personal relationship with Hun Sen. 

But a few days later, Hun Sen released the audio of his private call with Paetongtarn. It caused a huge uproar in Thailand, as Paetongtarn calls Hun Sen “uncle” and she refers to the Thai military as the “opposite side,” including accusing one top Thai general of “trying to look cool” by saber-rattling. Thai civil-military relations were already strained, and this greatly exacerbated those fissures, which nationalists and those aligned with Thai’s military exploited. Paetongtarn was suspended from her position in early July after the courts opened an ethics investigation against her. (Thailand’s top court formally removed her in August.)

Once on July 16, and again on July 23, a Thai soldier was injured by a landmine, which Thai authorities claimed Cambodia had recently planted. On July 24, serious fighting erupted near the Ta Muen Thom Temple, a Thai-administered temple near the border. Thailand blames Cambodia for deploying drones and for firing across the border with rocket-propelled grenades, allegedly killing 11 civilians and one soldier. Cambodia accused Thailand of attacking Cambodian troops, and that Cambodian soldiers only fired back in self-defense. The fighting intensified from there, with Thailand, the much stronger military power, launching air strikes against Cambodian troops. 

The Scramble for a Ceasefire

As this was unfolding, Malaysian Prime Minister Anwar Ibrahim rushed to mediate between Thailand and Cambodia. Anwar is the current president of ASEAN, and the regional organization has played the role of interlocutor between Thailand and Cambodia in the past, including in the 2011 dispute. ASEAN also has an incentive to have all of its members get along – or what’s known as the “ASEAN” way, consensus built through bilateral diplomacy, without too much interference from outside the region. 

Both China and the United States backed the Malaysian-lead ASEAN process. Thongchai Winichakul, a professor emeritus of history at the University of Wisconsin-Madison said that ASEAN’s effectiveness is limited. “Once major powers like China and the U.S. suggested to help, I think ASEAN welcomed that,” Winichakul said. 

“Of course, they know that this is opportunistic for Trump,” he added. “They know that this is opportunistic for China.”

China had tried to position itself as a peacemaker between Cambodia and Thailand even before hostilities escalated in late July, as Pongphisoot (Paul) Busbarat argued in a piece for the Carnegie Endowment for International Peace. Cambodia and China already have a tight relationship, and China funds and gives weapons to Cambodia’s military. Despite Thailand’s traditional ties to the U.S., Beijing has built stronger connections with Bangkok in recent years. Trump’s trade war also gave China an opening, not just to strengthen its economic influence (which is already pretty strong), but to flex its influence in the region. What’s more, China would prefer an ASEAN-led process over Western meddling or other mechanisms, so it makes sense it would back Malaysia’s efforts.

The role of U.S. officials is less clear, at least until Donald Trump got involved on July 26. On TruthSocial, Trump broadcast his diplomacy, which was essentially economic coercion. 

“Both Parties are looking for an immediate Ceasefire and Peace,” Trump wrote. “They are also looking to get back to the ‘Trading Table’ with the United States, which we think is inappropriate to do until such time as the fighting STOPS.”

Trump apparently phoned both leaders, telling them ceasefire or no trade talks. “The call with Cambodia has ended, but expect to call back regarding War stoppage and Ceasefire based on what Thailand has to say,” Trump wrote. “I am trying to simplify a complex situation!”

On “Liberation Day”, Trump slammed Southeast Asia with some of the steepest tariffs, including 36 percent for Thailand and 49 percent for Cambodia, though the administration eventually dropped that down to 36 percent for Cambodia in early July. Both were supposed to go into effect on August 1 – which, at the point of Trump’s phone calls, was just days away.

Those tariff levels were not sustainable for Thailand and Cambodia, and both had previously failed to make a deal with Washington. The U.S. is the biggest export destination for Thailand and Cambodia. U.S. tariffs at this level would have been existential to Cambodia’s textile sector. Both countries were already engaging with the U.S. to avert the worst of the trade shocks, so having Trump call the leaders of Thailand and Cambodia to basically offer tariff reductions in exchange for a ceasefire might not have seemed like a terribly bad deal – especially since the war itself was already going to be very disruptive economically for both countries. 

A few days after Trump’s calls, on July 28, Cambodia and Thailand agreed to an unconditional ceasefire. The joint press release from the Malaysian, Thai, and Cambodian governments mention both the U.S. and China, though it specifically calls out Trump and says he has been in contact with the leaders of both countries urging them to “find [a] peaceful solution to the situation.”

The ceasefire took effect on July 29, and though some skirmishes were reported, it has largely held. On August 1, the White House lowered the “reciprocal tariff rates” for Thailand and Cambodia to 19 percent.

Did Trump End this War? 

Trump’s tariff threat likely propelled mediation efforts that were already underway, and most observers and experts do think this probably did ease the way to a truce.

“We can debate President Trump’s motivation, and we can debate, as a whole, the U.S. government’s motivation behind this call,” said Raksmey Him, the executive director of the Cambodian Center for Regional Studies. “One thing for sure is that President Trump – I can tell you with some level of confidence – his action really has gotten Cambodia, and also Thailand, to stop fighting.”

Cambodia, especially, has been pretty effusive about praising Trump, and Prime Minister Hun Manet nominated Trump for the Nobel Peace Prize earlier this year. “President Trump’s extraordinary statesmanship — marked by his commitment to resolving conflicts and preventing catastrophic wars through visionary and innovative diplomacy — was most recently demonstrated in his decisive role in brokering an immediate and unconditional cease-fire between Cambodia and Thailand,” Hun Manet wrote in a letter to the Nobel Committee, which he also posted online, according to the New York Times.

Still, both Cambodia and Thailand agreed to these Kuala Lumpur Accords at ASEAN despite ongoing tensions. The declaration does offer meaningful steps to help Cambodia and Thailand ease tensions, but it doesn’t really offer a solution to the underlying issue: where the border actually sits, and who gets to control what. 

“The peace treaty is not the end of it, but as the beginning of a long step toward peaceful resolution between Cambodia and Thailand,” Him said.