In May 1965, then-Prince Norodom Sihanouk of Cambodia terminated diplomatic relations with the United States. In so doing, he altered his strict adherence of neutrality in foreign policy to align with the People’s Republic of China (PRC).
Sihanouk was in part acting in response to a derogatory article by Bernard Krisher for Newsweek that accused his mother, Queen Sisowath Kossamak, of running a bordello, along with an air raid by an American plane on a village in Kampong Cham province, which killed one teenage boy and injured a few others. Although these events may be viewed as the last straws that pushed Cambodia-U.S. ties to the breaking point, other factors — such as Pathet Lao’s victory at the Plain of Jarres in 1961, the downfall of Ngo Dinh Diem in 1963, and America’s alleged sabotaging efforts against his conference proposal — all played parts in the debacle.
In full: https://thediplomat.com/2019/12/cambodias-disastrous-dependence-on-china-a-history-lesson/