Vietnamization was a policy of the Richard Nixon administration to end U.S. involvement in the Vietnam War through a program to "expand, equip, and train South Vietnamese forces and assign to them an ever-increasing combat role, at the same time steadily reducing the number of U.S. combat troops". U.S. citizens' mistrust of their government that had begun after the Tet offensive worsened with the release of news about U.S. soldiers massacring civilians at My Lai (1968), the invasion of Cambodia (1970), and the leaking of the Pentagon Papers (1971). Nixon had ordered Kissinger to negotiate diplomatic policies with Soviet statesman Anatoly Dobrynin. Nixon also opened high-level contact with China. U.S. relations with the Soviet Union and China were of higher priority than South Vietnam. The policy of Vietnamization, despite its successful execution, was ultimately a failure as the improved ARVN forces and the reduced American and allied component were unable to prevent the fall of Saigon and the subsequent merger of the north and south, to form the Socialist Republic of Vietnam.