- 1) the abandonment of the Royal Court’s adherence to Hinduism and Mahayana Buddhism,
- 2) the adaptation of Theravada Buddhism that emphasis on simple life, opposing luxurious Royal Ceremony of god-king,
- 3) there were drought and failure of economic development as the intricate hydraulic system was not able to repair (Martin et al, 1989:10),
- 4) the total sacking of Angkor Wat capital city in 1444 and the rapid Southward expanding of Dai Viet,
- 5) eventually, the rise of Siam in Ayutthaya of Thailand in 1238 and the Dai Viet with their successful Nam Tien expansionism to the South.
The declining has continued affecting and exacerbating the politics in Cambodia in later 400 years before the arriving of French colony in 1863. The significant political situation that Cambodia firstly became a vassal state was likely during the King Barom Reachea IV in 1603 when Siamese successfully installed him in power; and also few years later King Chey Chettha II who was a successor to Barom Reachea declared independence from Siam by the assistance of military force from the Nguyen Dynasty of Vietnam (Martin et al, 1989:11). Cambodia has impressively been intervened by these two dominant countries, Thailand and Vietnam, since the declination of Angkorean period. There have had silence of Cambodia politics after independence in 1954, but during American war and Pol Pot regime, Vietnam headed Thailand because they can oust the Pol Pot and installed their vassal government. Although politics have significantly been changed since 1993 to present, but the installed leaders who assisted by Vietnamese military in 1978 are still in power nowadays.