History of Vietnam since 1945 unstable as no government could keep power for long. There were more coups, often more than one every year. The Communist-run Viet Cong expanded their operation and scored some significant military victories during this period. In 1965, US President Lyndon Johnson sent troops to South Vietnam to secure the country and started to bomb North Vietnam, assuming that if South Vietnam fell to the Communists, other countries in the Southeast Asia would follow, in accordance with the domino theory. Other US allies, such as Australia, New Zealand, South Korea, Thailand, the Philippines, and Taiwan also sent troops to South Vietnam.
1965 in the Vietnam War strikes, the U.S. 173rd Airborne began another sweep through Zone D with 2,500 men and ARVN and Australian participation. The allies claimed to have inflicted 100 Viet Cong casualties. Maxwell Taylor resigned as U.S. Ambassador to South Vietnam. Taylor had earlier been opposed to the introduction of U.S. ground troops into South Vietnam, proposing instead an intensified air campaign against North Vietnam. Taylor would be replaced by Henry Cabot Lodge, Jr., who returned to Saigon for his second stint as ambassador. The New York Times reported that the 173rd Airborne suffered 10 killed and 42 wounded on its sweep through