What happens when Sihanouk ties himself to the communist forces?

Convinced that the United States had been behind the overthrow, King Sihanouk allied himself with the Khmer Rouge at the urging of his Chinese patrons, giving the Cambodian Communists his prestige and enormous popularity. Their victory in 1975 brought the ruthless Pol Pot to power, with King Sihanouk serving, for the first year, as the figurehead president until he was placed under house arrest and fell into a deep depression. Over the next four years, the Khmer Rouge regime led to the death of 1.7 million people and nearly destroyed the country

google it and it will pop up