Geneva Accord
In 1966, Sihanouk made an agreement with Zhou En-lai of the People's Republic of China that would allow PAVN and VC forces to establish base areas in Cambodia and to use the port of Sihanoukville for the delivery of military material. The US, heavily involved in South Vietnam, was not eager to openly violate the asserted neutrality of Cambodia, which had been guaranteed by the Geneva Accord of 1954.