Airdrop Supplies to Marines during Operation Junction City, February 1967. Source: Wikipedia
In early 1967, General Westmoreland launched a series of concerted ground operations to both defeat embedded PAVN troops in North Vietnam and to disrupt the VCI, aiming to return “liberated zones” to the control of the Saigon government. This resulted in some of the bitterest fighting in the Vietnam War to date.
The most notable of these was Operation Junction City, launched in February 1967, in which US and South Vietnamese forces were involved in major attacks across so-called War Zone C against Viet Cong-held areas. The operation was the first airborne assault carried out by American troops since the Korean War and lasted a full three months. The ultimate aim of the operation was to locate and destroy the PLAF’s central headquarters in Tay Ninh province which American intelligence imagined as much larger and sophisticated than it actually was. At the outset of the battle, the outnumbered VC moved both its HQ and a large proportion of its forces across the border into Cambodian sanctuaries which, since the secret agreement with Sihanouk, had developed into a range of major military and administrative outposts. From here the guerrillas were able to launch a series of counter strikes against US and ARVN forces as they progressed through Tay Ninh. The result was heavy casualties on both sides, with the Communists suffering proportionally far more killed than the Americans. The local VCI was severely disrupted in the fighting and the overrun areas handed over to the South Vietnamese administration. As was becoming a familiar pattern however, for all the US expenditure of men and materiel, Saigon proved unable to comfortably hold Tay Ninh in the operation’s aftermath, which by the end of the year, had once again become heavily infiltrated by the Viet Cong.
The relative success of the Communist counter assaults from Cambodia during Junction City, also highlighted to American High Command just how important eastern Cambodia had now become to the Viet Cong war effort.