By mid-January 1967, the 271st and 272nd PLAF Regiments had recovered enough from previous defeats to redeploy from Cambodia into War Zone C. MACV intelligence had located the 271st on the Cambodian border near Lo Go, and the 272nd reportedly into the Michelin Rubber Plantation. The 9th Division’s third regiment, the 273rd, was located outside of War Zone C, but two other units of interest, the 101st PAVN Regiment and the 70th Guards Regiment, were both thought to be in the war zone. The 101st, normally part of the 7th PAVN Division, had now apparently come under permanent control of the 9th. The 70th Guards, about which little was known, was COSVN’s security unit. The presence of this unit not surprisingly stimulated General Westmoreland’s interest.

In the fall of 1966, Westmoreland had directed the II Field Force to develop plans for a major operation in War Zone C to engage and destroy large portions of the enemy in that area and eliminate COSVN. A major victory in the war zone would allow ARVN units “breathing space” to conduct meaningful pacification operations to win over the peasants in the countryside in support of the South Vietnamese government. The operation he envisioned, JUNCTION CITY, had been postponed by the need to conduct CEDAR FALLS first. By the third week of February, however, Westmoreland was set to begin this new offensive. His plan was to position units in the targeted area in such a way that he could spring JUNCTION CITY without arousing VC suspicions. Therefore, the two major units involved, the 1st and 25th Infantry Divisions, conducted separate deception operations to disguise their respective objectives.

The 25th Division’s effort, Operation GADSDEN, began in early February, and placed the Tropic Lightning’s units into War Zone C along the Cambodian border. The intent of GADSDEN was to draw the 271st from the border area farther east into the JUNCTION CITY target area. The Big Red One’s Operation TUCSON began almost two weeks later and was designed to appear as if the major focus was on the 272nd Regiment in the Michelin plantation area. The real targets, however, were both the 271st and 272nd Regiments and the COSVN headquarters. At the end of operations, GADSDEN would place the units attached to the 25th Division (3rd Brigade, 4th Division, and 196th Infantry Brigade) in positions to block escape routes into Cambodia. If conducted properly, TUCSON would accomplish three objectives: deceive the enemy as to where the big hammer would fall; position 1st Division units to initiate JUNCTION CITY; and drive the 272nd Regiment northwest, deeper into the trap with the 271st.

The Big Red One launched TUCSON on 14 February with the deployment of the 2nd and 3rd Brigades into the Long Nguyen Secret Zone (east of the Michelin Plantation) in Binh Long province. This area was considered to be the 272nd’s main base area and a supply route between War Zones C and D. The 3rd Brigade’s mission was to conduct a reconnaissance in zone to locate and destroy enemy forces and bases there. At 1117, 14 February, the 1st Battalion, 16th Infantry, operating as part of the 3rd Brigade, air assaulted into LZ 2, nine kilometers due east of the Michelin plantation. The LZ had been prepared by heavy artillery concentrations and the battalion landed without incident. The next three days were rather uneventful, save the battalion’s discovery and evacuation of 470 tons of rice and the wounding of ten Rangers by an incoming mortar barrage. On 17 February, the 1st Battalion was airlifted to posts along Highway 13 to conduct road clearing and security between Bau Long and Con Thanh. The 1st Battalion was now in position to begin JUNCTION CITY.

The 2nd Battalion did not participate in TUCSON in mid-February. Instead, 2-16 participated in Operation LAM SON 67, the ongoing joint pacification support operation conducted between units of the Big Red One and the 5th ARVN Infantry Division in Binh Duong province. During LAM SON, the Rangers sealed the village of Tan Phuoc Khanh as part of the division’s “Revolutionary Development” concept. On 22 February, however, the 2nd Battalion was pulled out of LAM SON to participate in JUNCTION CITY.