In a significant development reshaping Southeast Asia security, the United States and Cambodia are set to resume their joint military exercises, “Angkor Sentinel,” after an eight-year suspension. This pivotal decision, confirmed in late October or early November 2025 following high-level meetings between US Defence Secretary Pete Hegseth and Cambodian Deputy Prime Minister and Minister of National Defence General Tea Seiha, signals a profound diplomatic reset between the two nations and a dynamic shift in foreign policy shifts in global affairs.
This resumption marks a renewed commitment to military cooperation and rebuilding trust, contrasting sharply with the strained US-Cambodia relations that led to the drills’ hiatus in 2017. What prompted this dramatic turnaround, and what are its implications for regional stability and the broader Indo-Pacific strategy?
The Eight-Year Hiatus: A Period of Divergence
The “Angkor Sentinel” drills, initially launched in 2010 to strengthen military-to-military cooperation and enhance joint disaster relief capabilities, were abruptly halted in 2017. The primary catalysts for this suspension were deep human rights concerns and perceived democratic backsliding within Cambodia by the United States. Washington expressed serious reservations over actions such as the dissolution of the main opposition party, the Cambodia National Rescue Party (CNRP), and the arrest of its leader, Kem Sokha, on treason charges.
Furthermore, the US criticized the curtailment of freedoms of speech, assembly, and association, alongside restrictions on independent media. These concerns led to concrete responses from the US, including visa restrictions on individuals undermining Cambodian democratic governance and aid reductions totaling approximately $8.3 million in 2018. This period of frosty relations also coincided with Cambodia’s increasing alignment with China, a factor Washington closely monitored.
Image 1: Strained Relations & Democratic Concerns. A visual representation of the human rights concerns and democratic governance issues that led to the hiatus in US-Cambodia relations.
Cambodia’s Pivot to Beijing: Deepening Ties with China (2017-2025)
During the eight-year hiatus from “Angkor Sentinel,” Cambodia significantly deepened its strategic partnerships with China, transforming Beijing into its primary military and economic ally. This era was characterized by substantial Chinese investment, aid, and expanded military cooperation. A cornerstone of this relationship was the extensive refurbishment and expansion of Cambodia’s Ream Naval Base, largely funded by China since 2022 and officially inaugurated in April 2025. While Cambodia maintains the base remains under its sovereignty and open to all “friendly countries,” the US and other Western nations have voiced concerns that it could serve as a Chinese military outpost, impacting Indo-Pacific strategy.
Joint military exercises with China, known as “Golden Dragon,” grew steadily in scale, replacing the suspended “Angkor Sentinel” drills. The May 2025 iteration was the largest to date, involving nearly 900 Chinese and over 1,300 Cambodian military personnel, along with advanced Chinese hardware. China also became Cambodia’s most significant military supplier, providing equipment, training, and substantial grants.
Economically, China solidified its position as Cambodia’s largest foreign investor, creditor, and donor. The Belt and Road Initiative (BRI) drove numerous infrastructure projects, including expressways, ports, and airports, such as the Phnom Penh-Sihanoukville Expressway and the Siem Reap Angkor International Airport. By 2024, Chinese Foreign Direct Investment (FDI) inflows reached $3.4 billion, accounting for about 75% of Cambodia’s total FDI. While these ties brought economic growth, concerns about Cambodia’s increasing dependence on Beijing and the sustainability of its debt mounted.
Image 2: Ream Naval Base Expansion. An aerial view highlighting significant Chinese investment and China’s growing influence in Cambodia.
A New Dawn: The Resumption of Angkor Sentinel
The decision to restart the Angkor Sentinel drills marks a pivotal moment, signaling a desire from both Washington and Phnom Penh to reset their relationship. This diplomatic reset comes amidst a broader warming of ties, bolstered by several key developments. US President Donald Trump’s administration has been instrumental, facilitating a Trump-backed peace accord between Cambodia and Thailand and securing a new trade deal during a three-nation Asian tour. Furthermore, the US lifted a four-year arms embargo on Cambodia on November 7, 2025, removing a major point of contention.
Discussions are also underway for a future visit by a US naval ship to Cambodia’s Ream Naval Base, a move that could potentially alleviate some international concerns about exclusive Chinese military access. The re-opening of enrollment for Cambodian military students to study at prestigious US institutions like West Point further underscores the commitment to renewed military cooperation and trust-building. Analysts view this as Washington’s renewed interest in Southeast Asia security and offers Cambodia a valuable opportunity to diversify its strategic partnerships beyond its substantial ties with China.
Image 3: Handshake of Diplomacy. US Defence Secretary Pete Hegseth and Cambodian Deputy Prime Minister General Tea Seiha symbolize the diplomatic reset and renewed US-Cambodia relations.
Understanding Angkor Sentinel: Purpose and Focus
The “Angkor Sentinel” exercises, jointly conducted by the U.S. Army Pacific (USARPAC) and the Royal Cambodian Army, have a well-defined purpose. They are designed to train both forces for peacekeeping operations and stability missions, while also enhancing capabilities in humanitarian assistance and disaster relief.
Historically, the drills have included a battalion-level command post exercise (CPX), an engineer civic action project (ENCAP), and medical civic action projects (MEDCAP). Training areas typically cover first aid, engineering skills, explosive ordnance disposal (EOD), countering improvised explosive devices (C-IED), and logistical support. For instance, Angkor Sentinel 2010 focused on providing assistance and training to the Royal Cambodian Armed Forces and was considered crucial for building successful regional military-to-military relationships. The 2016 iteration emphasized collective strengthening of both countries’ humanitarian and disaster relief capabilities, reflecting a shared commitment to regional stability and addressing common challenges.
Image 4: Joint Humanitarian Training. US and Cambodian soldiers demonstrate effective military cooperation in humanitarian assistance during a simulated mission.
Strategic Implications: Balancing Act in Southeast Asia
The rekindling of Angkor Sentinel drills signifies more than just renewed military exercises; it represents a complex balancing act in Southeast Asia security. For the United States, it underscores a proactive Indo-Pacific strategy aimed at strengthening alliances, promoting regional stability, and offering alternatives to growing China influence. It suggests Washington is willing to engage diplomatically to address past grievances and re-establish its presence in a geopolitically crucial region.
For Cambodia, this diplomatic reset provides an invaluable opportunity to diversify its strategic partnerships and reduce its perceived over-reliance on Beijing. While deep ties with China will undoubtedly continue, re-engaging with the US offers Cambodia greater foreign policy flexibility and access to different forms of military training and support, enhancing its national security. This move demonstrates Cambodia’s intent to navigate the complex geopolitical landscape by maintaining relationships with multiple major powers.
Conclusion: A New Chapter in US-Cambodia Relations
The resumption of the “Angkor Sentinel” military drills marks a hopeful new chapter in US-Cambodia relations. After an eight-year hiatus fueled by human rights concerns and shifting geopolitical alignments, this diplomatic reset reflects concerted efforts to rebuild trust and foster greater military cooperation. While the landscape of Southeast Asia security has evolved significantly since 2017, with increased China influence and an evolving Indo-Pacific strategy, the rekindling of these drills offers a pathway toward enhanced regional stability and diversified strategic partnerships. As both nations move forward, the focus on peacekeeping operations and humanitarian assistance within “Angkor Sentinel” underscores a shared vision for a more secure and cooperative future in global affairs.
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