On April 30, 1967, Prime Minister Lon Nol resigned. He was replaced by Son Sann.
On April 30, 1970, President Nixon publicly announced the ‘Cambodian incursion’, triggering anti-war demonstrations across the US.
On 30 April, 1972, a new constitution was ratified. Political parties formed in the new nation, quickly becoming a source of political factionalism. General Sutsakhan stated: “the seeds of democratization, which had been thrown into the wind with such goodwill by the Khmer leaders, returned for the Khmer Republic nothing but a poor harvest.” By now, key plotter against Sihanouk- Sirik Matak- had been placed under virtual house arrest by Lon Nol.
On 30 April 1975, the last American helicopters left from Saigon as tanks of the North Vietnamese Army moved into the capital of a defeated South Vietnam.
On April 30, 1999, Cambodia was admitted to be the 10th member of ASEAN, following the deferral in 1997 due to internal political crisis and after years of being a regional observer.
On May 1, 1975, Khmer Rouge forces invaded the Vietnamese island of Phu Quoc and claimed it as part of Cambodia- reportedly raising the plain red flag of revolution on the beach. The Provisional Revolutionary Government of South Vietnam (the country would not officially unify for over a year after the fall of Saigon) sent helicopters to strafe the beach. The Cambodians were finally forced off when a contingent of North Vietnamese Army troops arrived to clear them from the island.
On May 1, 1981, parliamentary elections were held- the Kampuchean People’s Revolutionary Party (KPRP) won 117 out of 117 seats in the National Assembly.
On May 1, 1989, the national flag was changed.
On May 3, 1965, Cambodia severed diplomatic relations with the US. Philip Dodson Sprouse would be the last US Ambassador for over 4 years.
On May 3, 1977 The United States Congress began a hearing into claims of genocide in Cambodia.
On May 4, 1970, anti-war protests in the US turned violent- spurred on by the invasion of Cambodia. National Guardsmen fired on anti-war demonstrators at Ohio’s Kent State University, killing four students and wounding nine.
On May 5, 1975, US intelligent reports claimed that dozens of Cambodian military officers and their wives had been executed.
On May 6, 1947, the first Cambodian Constitution was passed. Cambodia became a constitutional monarchy.