Cambodia is the country in Southeast Asia with the smallest ethnic minority population, both relatively and in absolute numbers. Among about 10 million inhabitants almost 90 per cent are ethnic Khmer. Khmer dominance is ancient: for the Khmer, the kingdom of Angkor (ninth to fifteenth centuries) still remains very much the exemplary origin both of Khmer civilization and the Cambodian nation.SOURCE: "Cambodia," by Jan Ovesen and Ing-Britt Trankell, in Ethnicity in Asia, ed. by Colin Mackerras (RoutledgeCurzon, 2003), pp. 194-195
The ways in which governments, officials and elites in post-colonial Cambodia have perceived and treated the country's non-Khmer ethnic groups reflect an attitude of Khmer supremacy. This attitude is not so much directed against other ethnic groups (except for the Vietnamese), as manifesting a profound ethnocentrism, a conviction that Khmer culture is superior to others. This ethnocentrism puts the Khmer in line with the constructivist view, as opposed to the essentialist .... Already at independence (1953) it was officially recognized that one could 'become Khmer' (coul kmae) by adopting the Khmer language and customs.
The Khmer see themselves as fundamentally agrarian, their primary crop, paddy rice, being not only the mainstay for all but an important symbol of the human condition in general. Consequently, the ideal society is one of rice-farming peasants. It was the Khmer Rouge that most explicitly pursued this ideal, but cities generally do not figure positively in the Khmer imagination. There is an implicit association between urban life and foreign, non-Khmer customs. From a Khmer perspective, the capital Phnom Penh is a place in some sense outside Khmer cultural space and inhabited mainly by 'foreigners'. The traditional 'foreigners' in Cambodia are the Chinese and the Vietnamese, and these have always to a large extent been urban populations. The rural-urban dichotomy is thus a significant dimension of ethnic relations.
Historically Cambodia has felt politically and territorially pressed between its two more powerful neighbours, Siam (Thailand) and Annam (Vietnam). Siamese armies contributed to the fall of Angkor in the late fifteenth century, and Cambodia was effectively under Siamese suzerainty for much of the period after this until becoming a French protectorate in 1863. Thailand temporarily annexed the northwestern provinces of Battambang and Siem Reap (where Angkor is located) during the Second World War; the name Siem Reap means 'Siam conquered', perhaps implying conquered both by and from Siam.
Nevertheless, since independence, the Cambodian governments and the Khmer educated elite have always regarded Vietnam and the Vietnamese as the big threat to Cambodian political, economic and territorial sovereignty, not Thailand and the Thais. Thus, the Khmer consider the Mekong Delta as kampuchea krom, a Cambodian territory unlawfully annexed by Vietnam. The Cambodian border provinces of Prey Veng and Svay Rieng have a significant Vietnamese rice-farming population who have settled ('encroached') in search of land. Vietnamese expansionism is a recurrent theme in Khmer propaganda.
The main cultural divide running through Indochina is that which divides mainland Southeast Asia between the 'Indianized' states of Burma, Thailand, Laos and Cambodia and the 'Sinicized' Vietnam. This cultural divide may explain why the attitude of the Khmer towards the Vietnamese is significandy different from that towards the Thai. So, also culturally speaking, both Vietnamese and Chinese are perceived as foreign. But in contrast to the Chinese, the Vietnamese in Cambodia are regarded by the majority of the Khmer as intruders, whose presence in the country many perceive as a threat to the Khmer-ness of the nation. Although the Vietnamese do not form one coherent ethnic community, the Khmer nationalist elite, who have pursued anti-Vietnamese propaganda since independence, have tended to ignore this fact, and little allowance has been made for the diversity of Vietnamese communities within the ethnic category 'Vietnamese'. Consequently, all members of this category have been victims of violent persecutions in recent Cambodian history.