In late February 1967, Operation Junction City was the largest American and Vietnamese operation of the war: 24 American infantry, cavalry, and artillery squadrons and battalions, two tough South Vietnamese marine battalions, and untold numbers of engineers and support troops swarmed the Tay Ninh province, known as War Zone C, to search for and destroy the Central Office of South Vietnam, or COSVN, the main Viet Cong headquarters, and the base areas of the 9th VC Division. They found almost nothing.
The massive operation did uncover numerous caches of rice and ammunition, and even COSVN’s photo lab, but actual contact with the VC was almost nonexistent. This was greatly disappointing for the LTG Seaman, the US III Corps/II Field Force commander, and Gen Westmoreland, the US Military Assistance Command – Vietnam (MAC-V) Commander. Westmoreland had seen the South Vietnamese Army nearly wiped out by Communist main force units in 1964-65 while they conducted village pacification (hence increased American involvement in 1965), and he wasn’t about to make the same mistake. He needed to find and destroy the big communist units before he could disperse his battalions into the countryside and protect the population. Junction City was supposed to isolate and destroy the largest Communist formation threatening Saigon: the 9th VC Division and its attachment of regular North Vietnamese Army troops, the elite 101st Infantry Regiment. But they were gone.
Gen Nguyen Thi Thanh, the COSVN commander, pulled them back into Cambodia after the serious losses they took during Operation Attleboro the November before. Upon their return to South Vietnam, he wanted to engage the Americans again. His rival, Gen Vo Nguyen Giap, the commander of the North Vietnamese Army, wanted them to cease the wasteful and “suicidal” attacks on American units, and conduct a guerilla campaign in the South. Thanh did not, and thought Giap “soft” for not wanting to engage the Americans: the French were thrown out of North Vietnam precisely by targeting French army units whose destruction greatly increased Vietnamese morale, and led directly to a popular uprising in North Vietnam. Furthermore, the American casualties would inflame the burgeoning Soviet sponsored American antiwar movement, which would ultimately lead to America’s withdrawal, as it had the French. Thanh wanted to do the same. Fortunately for Thanh, Giap wasn’t his commander: Thanh reported directly to the Party in Hanoi. He would get his chance to attack the Americans.
After the initial first few days’ disappointment, American engineers began building firebases and Special Forces’ camps in War Zone C to hold the area, and prevent further Communist infiltration from Cambodia. Thanh saw this as an opportunity to defeat the spread out American battalions in detail. On 27 February, the 101st NVA Regt infiltrated into Tay Ninh and the next day assaulted the 1/16 Infantry battalion of the 1st Infantry Division on a search and destroy mission outside of Prek Klok. Though the American fought off over four hours several assaults by the Vietnamese, casualties on both sides were heavy. On 3 March, the COSVN’s own security battalion attacked a paratrooper battalion of the 172nd Airborne Brigade, the short 30 minute fight killed 25 Americans and wrecked two entire infantry companies, and only superior firepower prevented the battalion’s complete destruction. A week later the 101st came back for Prek Klok, and again were fought off. On 19 March, the entire 273rd VC Regiment locked horns with the tanks and armored personnel carriers of the 3rd squadron of the 5th Cavalry in the Battle of Ap Bau Bang II. It was a bold move to fix the 11th Armored Cavalry Regiment, which was ultimately successful, though devastatingly costly. All along the border, the now static American battalions were assaulted, and more importantly fixed, by the increasing numbers of VC infiltrating from Cambodia.
Westmoreland wanted his big unit fights and though these weren’t exactly as big as he was hoping, they would do for the time being.
But as the old saying goes, “Be careful what you wish for” – These were just Thanh’s opening moves.