The November 1, 1963 coup that overthrew South Vietnamese President Ngo Dinh Diem had unleashed a wave of political instability that Communist forces were eager to exploit. In the period following Diem's assassination through mid-1965, the South Vietnamese government had five different chiefs of state before General Nguyen Van Thieu became the figurehead in what was in actuality a military junta. Raids by the National Liberation Front, or Viet Cong, picked up in frequency and intensity following Diem’s ouster.
In early February of 1965, President Johnson sent a delegation headed by Special Assistant for National Security Affairs McGeorge Bundy to Vietnam. After returning to Washington Bundy reported
The situation in Vietnam is deteriorating, and without new U.S. action defeat appears inevitable--probably not in a matter of weeks or perhaps even months, but within the next year or so. There is still time to turn it around, but not much.
Bundy had been in Vietnam on February 7, when the Viet Cong attacked the U.S. Army helicopter facility at Camp Holloway in the Central Highlands, near the city of Pleiku. In that incident eight U.S. soldiers were killed and another 126 were wounded, while ten aircraft were destroyed and 15 were damaged. Only three days later, Viet Cong operatives detonated explosive charges at a hotel used as a U.S. Army enlisted men's billet in the coastal city of Qui Nhon, killing 23 U.S. servicemen. Those two incidents were in turn met with U.S. air strikes, as the first and second stages of Operation Flaming Dart.
Operation Flaming Dart
Only twelve hours after the attack at Camp Holloway, 49 U.S. fighter-bombers took off from U.S. aircraft carriers to attack barracks and staging areas in Dong Hoi, just north of the Vietnamese Demilitarized Zone (DMZ). These facilities were used by Hanoi for the training of Viet Cong personnel and for their infiltration into South Vietnam. In response to the Qui Nhon hotel bombing, a combined force of about 160 U.S. and South Vietnamese fighter-bombers targeted guerrilla staging areas and communications centers at Chap Le and Chanh Hoa, also located just north of the DMZ. In this second stage of Flaming Dart, 28 U.S. Air Force F-100 Super Saber jet fighters flying from Da Nang air base participated, marking the first use U.S. Air Force of jet aircraft in the Vietnam conflict.
On February 7, the day of the attack at Camp Holloway, President Lyndon B. Johnson announced the withdrawal of all American dependents from South Vietnam. The statement announcing the decision contained this comment:
In addition to this action, I have ordered the deployment to South Viet-Nam of a Hawk air defense battalion.
HAWK air defense systems were mobile, surface-to-air guided missile systems that defended against low-flying aircraft and were additionally capable of intercepting short-range missiles. U.S. Marine Corps Light Antiaircraft Missile (LAAM) Battalions were responsible for their operation. On February 7 the commanding officer of the 1st LAAM Battalion, which was stationed in Okinawa, received orders to move one HAWK battery to Da Nang. The air base in that city was used by U.S. jet fighters as a launch point for attacks across the DMZ, therefore it required protection. Nine days later, a second battery was deployed to the Da Nang airfield complex.
The Arrival of the 9th Marine Expeditionary Brigade
Confronted with deteriorating political and military situations, joint-service commander General William Westmoreland requested that a two-battalion Marine Expeditionary Brigade be deployed to Da Nang, due to the vital importance of the air base and the questionable capability of the South Vietnamese to protect it. President Johnson agreed to this request and on March 8, 1965 the 3rd Battalion, 9th Marines came ashore at the Red Beach Base Area, northwest of Da Nang, becoming the first American conventional ground combat unit in South Vietnam.