On 18th March 1970, while Prince Sihanouk was out of the country visiting Moscow, Lon Nol, in collaboration with Deputy Prime Minister Sisowath Sirik Matak, launched his much-anticipated coup against Sihanouk. Lon Nol declared himself premier and quickly obtained the support and approval of the National Assembly. Shortly thereafter Lon Nol abolished the Cambodian monarchy and declared the establishment of the Khmer Republic. The grievances of the Cambodian Right were well known - disagreement with Sihanouk’s leftist economic policies certainly, but overwhelmingly huge frustration at the prince’s tolerance of the occupation of eastern Cambodia by the NVA and his apparent insouciance at the growth in strength and influence of the Khmer Rouge in rural areas.