A weakened Khmer state after repeated warfare with Siam in the 17th century left the Mekong Delta poorly administered. Concurrently Vietnamese refugees fleeing the Trịnh–Nguyễn War in Vietnam pushed into the area. Cambodian king Chey Chettha II (1618–1628) in 1623 officially sanctioned the Vietnamese to operate a custom house at Prey Nokor, then a small fishing village. The settlement grew steadily as a major regional port, attracting even more settlers.
The Nguyễn Lords of Huế in 1698 commissioned Nguyễn Hữu Cảnh, a Vietnamese noble, to organize the territory along Vietnamese administrative lines, thus by de facto detaching it from Cambodia and joining it to Vietnam.
With the loss of the port of Prey Nokor, then renamed Sài Gòn, Cambodia's control of the area grew increasingly tenuous while increasing waves of Vietnamese settlers to the Delta isolated the Khmer of the Mekong Delta from their brethren in Cambodia proper. By 1757, the Vietnamese had absorbed the provinces of Psar Dèk (renamed Sa Đéc in Vietnamese) on the Mekong itself, and Moat Chrouk (Vietnamized to Châu Đốc) on the Bassac River.
On June 4th 1949, the French President, Vincent Auriol, signed the law granting Cochin-China to the Bao Dai government without consultation of the indigenous Khmer-Krom. Cambodia was then cut off from direct access to the South China Sea at that point. Left within the borders of Vietnam were large pockets of Khmer people, now known as the Khmer Krom.
Separatist movements[edit]
Khmer nationalist Son Ngoc Thanh (1908–77) was a Khmer krom, born in Trà Vinh, Vietnam. Thanh was active in the independence movement for Cambodia. With Japanese support he became the prime minister of Cambodia in March 1945 but was then quickly ousted with the return of the French later that year. Widely supported by the Khmer Krom during the First Indochina War, Thanh's role faded in Vietnam after 1954 as he became more embroiled with politics in Cambodia proper, forming an opposition movement against Prince Sihanouk.
During the Vietnam War and direct American involvement between 1964 and 1974, the Khmer Krom were recruited by the US military to serve in MIKE Force.[5] The force fought on the side of South Vietnam against the Viet Cong but in time the militia regrouped as the "Front for the struggle of Kampuchea Krom" (French: Front de Lutte du Kampuchea Krom). Headed by a Khmer Krom Buddhist monk, Samouk Sen, the group was nicknamed the "White Scarves" (Khmer: Kangsaing Sar; Vietnamese: Can Sen So) and allied itself with FULRO against South Vietnam.[6]
