The peace envisaged by the treaty lasted only two years. The Pathet Lao refused to disarm and the PAVN did not leave the country. In late February 1975, the Pathet Lao with PAVN assistance, began attacking government strongholds on the Plain of Jars. With the fall of the Cambodian government to the Khmer Rouge on 17 April and the fall of the South Vietnamese government to the PAVN on 30 April 1975 the non-communist elements of the national government decided that allowing the Pathet Lao to enter power would be better than to have them take it by force. Long Tieng was evacuated in mid-May. On 23 August 1975, Pathet Lao forces quietly entered the capital Vientiane.