Cambodian Coup of 1970
Sirik Matak's power increased substantially after Lon Nol became Prime Minister in August 1969. Appointed Lon Nol's deputy, he proceeded to organise a series of economic denationalisation and deregulation measures in opposition to Sihanouk's previous policy of state control of import and export, banking, and production of pharmaceuticals and alcohol. Sirik Matak even visited Hanoi secretly to find out what could be done to remove Vietnamese troops from Cambodian soil. He was infuriated when he was shown documents signed by Sihanouk agreeing to the establishment of Vietnamese bases and the transport of Vietnamese supplies through Cambodian ports. On March 12, 1970, while Sihanouk was on a trip abroad, Sirik Matak canceled Sihanouk's trade agreements and Lon Nol demanded that all North Vietnamese and NLF troops leave Cambodia by dawn on March 15 (the deadline passed without any response from the Vietnamese). On March 18, Sirik Matak assisted Lon Nol in organising a vote of the National Assembly to depose Sihanouk as head of state. The pretext was given by a series of anti-Vietnamese riots - likely encouraged by the Prime Minister and his deputy - in front of the North Vietnamese embassy. Foreign media subsequently suggested that Sirik Matak, who continued as Lon Nol's deputy in the new government, was the real organisational force behind the coup; it was claimed that in order to finally convince Lon Nol, Sirik Matak had played him a tape-recorded press conference from Paris, in which Sihanouk threatened to execute them both on his return to Phnom Penh. It was even reported that Sirik Matak compelled Lon Nol at gunpoint to commit to deposing Sihanouk.
Sihanouk also assumed his cousin to be the main force behind the coup, claiming that Sirik Matak (backed by the CIA, and in contact with long-time Sihanouk opponent Son Ngoc Thanh) had already suggested the plan to Lon Nol as early as 1969. Sihanouk's suspicions seem to have rooted in fact: Prom Thos, one of Lon Nol's ministers, later told the historian Ben Kiernan that in around March 1969 Sirik Matak had argued that Sihanouk should be assassinated, Lon Nol rejecting the plan as "criminal insanity".
With the declaration of the Khmer Republic subsequent to the coup, Sirik Matak renounced his royal title, although he had initially planned in secret that his own son, or another member of the Sisowath family, possibly his son-in-law Prince Sisowath Duongchivin, should take the throne.
Lon Nol's regime was behind the massacre of thousands of ethnic Vietnamese residents in the period immediately after the takeover. There is evidence that Sirik Matak may have privately made efforts to halt these killings.
Read more about this topic: Sisowath Sirik Matak