It won an overwhelming victory in the elections: there were subsequently allegations of massive electoral fraud, and of intimidation directed against both the opposing Democratic Party and the socialist Krom Pracheachon.
[13] Sihanouk's method of alternately criticising his opponents in various public forums, and then of offering them posts within the Sangkum in a demand that they positively contribute to Cambodian society, had the dual effect of stifling dissent and of integrating much of the opposition into his regime.
The only notable element to remain outside the Sangkum, other than the hardline communists, was the right-wing, anti-monarchist nationalist Son Ngoc Thanh, whose Khmer Serei irregulars maintained armed resistance with funding from Thailand.
[18] However, it seems that during the late 1950s and early 1960s there was relatively little violent repression of opposition to the Sangkum (although there was repeated political intimidation of the leftist Pracheachon party, who were accused of being pro-Vietnam) and the country as a whole experienced a period of comparative stability.
The 1966 elections resulted in an overwhelming victory for rightist candidates; Sihanouk responded by creating a left-wing "Counter-Government", including Hu Nim and Khieu Samphan, to act as a check, and prevent the regime splitting completely.
Increasingly violent repression of the left, led by Lon Nol and the military in Sihanouk's name, came to alienate many of the remaining communists, especially the more moderate pro-Sihanouk faction who owed a strong allegiance to Vietnam and the Viet Minh.
The Sangkum found itself locked in an increasingly bitter struggle with what it represented as 'foreign' elements of the Viet Minh and Pathet Lao within Cambodia: speaking on Phnom Penh radio after a group of Vietnamese communists was captured, Sihanouk stated that "I had them roasted [...] we had to feed them to the vultures".
The three remaining public representatives of the communists – Khieu Samphan, Hou Yuon and Hu Nim – fled to the forests in 1967-8, though at the time it was widely rumoured that they had been murdered by the Sangkum's police (after their reappearance in the 1970s, they were referred to in the press as the "Three Ghosts").
Many commentators, particularly those on the left or those personally opposed to Sihanouk, have described the Sangkum as essentially a conservative movement which sought to maintain the power and influence of the Cambodian status quo through authoritarianism.
[23][24] Others, however, have noted that it vastly increased the participation of ordinary Cambodians in democracy, and describe it as a pragmatic movement which genuinely sought to bring community development to Cambodia through "expert guidance and gentle persuasion".