It has long been rumored that the government of Cambodia would offer China a military outpost, most likely a port facility, in its territory. The speculation took concrete form this week following a Wall Street Journal report that the two governments had concluded a secret agreement that would give Beijing access to a navy base in the south of Cambodia. Despite heated denials from Phnom Penh, there are good reasons to believe the reports are accurate. Such an agreement would mark a critical moment in Southeast Asian security and potentially transform the regional security outlook.

China has long sought access to port facilities in South and Southeast Asia. Strategists have referred to a "string of pearls," a network of ports and logistics facilities that would allow China to project power throughout those regions — ostensibly to protect Chinese interests, in particular trade that transits those areas, but also to threaten those of potential adversaries. One study identified 42 ports in 34 countries where Chinese firms have been involved in construction and which could serve China's strategic interests. Key nodes include the ports of Gwadar in Pakistan, Hambantota in Sri Lanka, Kyaukpyu in Myanmar and Sihanoukville in Cambodia.

Cambodia is an especially valuable target since it is centrally located in Southeast Asia and the government of Prime Minister Hun Sen has cultivated close ties with Beijing. China has become Cambodia's biggest investor and source of aid. In 2017, it invested nearly $1.5 billion in Cambodia, about 70 percent of total foreign direct investment, and fuel for the country's 7 percent economic growth. In addition to jobs, funds grease the pockets of Cambodian decision-makers and facilitate patronage and corruption. China has also provided diplomatic cover for the authoritarianism and human rights abuses of the Hun Sen government.