MC EXPLAINER Guns down, mines open: The rare-earth agenda behind Trump’s ‘peace’ in Southeast Asia

The Real Story Behind Trump’s ASEAN Triumph: Rare Earths, Trade Power and a Quiet New Cold War

When U.S. President Donald Trump strode into the ASEAN Summit in Kuala Lumpur, flags in both hands and cameras flashing, the headline moment seemed straightforward: a dramatic ceasefire between Thailand and Cambodia, ending months of artillery skirmishes along their disputed border.

But behind the stagecraft of peace, another negotiation was unfolding, one with potentially longer-term impact than any truce.

Alongside the ceasefire signing, the United States inked trade and critical-minerals cooperation agreements with Thailand, Cambodia and Malaysia, according to government releases and media briefings reported by Reuters.

The timing wasn’t incidental. As the two Southeast Asian neighbours pledged to withdraw troops and release prisoners, US trade envoys were busy formalising agreements that would help American firms secure alternative supply chains for minerals used in electric vehicles, semiconductors and defence systems, the same resources where Beijing dominates global refining.

“It’s very important that we cooperate as willing partners to ensure we have smooth, secure supply chains for our people and our security,” said US Trade Representative Jamieson Greer at the summit.

Peace with a price tag

The ceasefire, signed by Cambodian Prime Minister Hun Manet and Thai Prime Minister Anutin Charnvirakul, calls for Thailand to release 18 detained Cambodian soldiers and for both sides to withdraw heavy artillery from their 800-kilometre frontier. Regional observers will monitor compliance.

But the deal’s location and choreography, announced on the sidelines of a forum designed for economic cooperation, make clear that diplomacy and trade have become inseparable.

According to the US Geological Survey (USGS) and ASEAN trade records, Thailand and Cambodia sit on valuable deposits of tin, tungsten, antimony and rare earths, minerals essential to next-generation electronics and green energy. A 2024 US Department of Energy paper identified Thailand as a 'strategic diversification partner' for rare-earth refining. Cambodia’s proximity to Thailand’s Laem Chabang port and its coastal corridor to Sihanoukville offer a natural logistics chain.

That’s what makes border stability worth underwriting. Before the July clashes, the Thai Commerce Ministry estimated more than $3 billion in trade and infrastructure projects were at risk along the frontier.

“The tariff card that Trump played was decisive,” Ou Virak, president of Phnom Penh’s Future Forum think tank, told Reuters. “It wasn’t just about peace, it was about access and leverage. Once trade deals were at stake, both sides suddenly found common ground.”

Critical minerals as the quiet prize

By tying ceasefire diplomacy with mineral and supply-chain talks, the US is advancing its broader Indo-Pacific economic strategy: reduce dependency on China while deepening commercial roots in ASEAN.

China currently refines around 70 percent of global rare-earth output, according to the International Energy Agency. It has tightened exports of metals like gallium and germanium, spooking manufacturers and prompting Washington to hunt for new partners.

Southeast Asia’s mineral belt, stretching from Vietnam through Thailand, Laos and Malaysia, is emerging as a substitute. For the US, every 'peace corridor' that becomes safe for investment is also a node in its alternative supply network.

ASEAN’s new balancing act

For ASEAN, the US engagement brings investment and visibility, but also a challenge. The bloc must demonstrate that its diplomacy can secure both stability and autonomy.

Malaysia’s Prime Minister Anwar Ibrahim, who hosted the summit, praised the Cambodia–Thailand accord as proof that “reconciliation is an act of courage, not concession.”

Yet regional analysts caution that aligning with Washington’s economic push could sharpen tensions with Beijing, ASEAN’s largest trading partner. For Thailand and Cambodia, the payoff is immediate funding; the trade-off is long-term dependence.

“This is peace-through-profit, it’s sustainable only as long as the money flows,” a Bangkok-based diplomat told The Guardian on background.

India’s absence 

Notably missing from Kuala Lumpur was Prime Minister Narendra Modi, even as India has been courting ASEAN partners for critical-minerals collaboration under its Mines and Minerals Policy 2024.

That absence leaves Washington freer to define the region’s resource geography, and gives New Delhi a signal that its Indo-Pacific engagement risks being overshadowed by American deal-making.

If border troops truly withdraw and investment resumes, the peace will hold, and the US will have turned a once-volatile frontier into a functional economic corridor. If not, it may reveal the limits of using trade pressure as diplomacy. Either way, in Southeast Asia’s new geopolitics, lithium and leverage travel together.