It was during one such operation, in which the 1st and 2d VNMC Battalions were operating together in the provinces south of Saigon, that elements of the 3d Battalion became involved in the abortive coup of November 1960. The power struggle began in the early morning hours of the 11th while the U.S. Marine advisors were attending an informal celebration of the Marine Corps birthday at Lieutenant Colonel Robichaud’s quarters in Saigon. At the appointed hour Colonel Thi’s rebellious paratroops, accompanied by the 3d VNMC battalion commander and two Marine companies from Cuu Long, moved into the capital on trucks and seized the Joint General Staff Headquarters. The remainder of the 3d battalion, led by the battalion executive officer, who was unaware of his superior’s intentions, moved to the presidential palace and established protection for Diem. Word of the coup, meanwhile, had reached Khang at his field headquarters in the Mekong Delta. Led by the Senior Marine Officer, the 1st and 2d Battalions returned to Saigon by truck convoy and immediately joined the two Marine companies already around the palace. For several hours the possibility existed that Khang’s Marines might clash with Thi’s paratroops or even with the two rebellious Marine companies of the 3d Battalion. But pro-Diem units soon began converging on Saigon in such numbers that the coup collapsed. Thi and his associates fled the country, whereupon Diem appointed new officers to command the insubordinate units. With loyalists in charge throughout South Vietnam’s military and naval services, the incident was closed. Both the airborne brigade and the VNMC resumed their functions as the RVNAF general reserve.[3-12] By the summer of 1961 the USMAAG, now headed by General McGarr, was ready to implement the 20,000-man expansion of the RVNAF as authorized in the package approved by President Kennedy the previous spring. Included in this U.S. program were plans to increase the size of the Vietnamese Marine Corps by over 1,000 men. This expansion got underway in July when the initial steps were taken to form a fourth infantry battalion and a 75mm pack-howitzer battery--additions which were to raise the authorized strength of the VNMC to 3,321 officers and men. The transfer of ARVN artillerymen provided the personnel necessary to man the pack-howitzer unit, which formed near Thu Duc, a small town about 13 miles north of the capital. Officers and noncommissioned officers were drawn from the three existing VNMC battalions to form a nucleus for the new infantry battalion while its ranks were filled gradually by recruitment. This 4th Battalion was organized at Vung Tau, a coastal resort town situated on Cape St. Jacques about 40 miles southeast of Saigon. Lieutenant Colonel Robert E. Brown, a World War II veteran who replaced Robichaud as Senior Marine Advisor in August, was on hand to assist with this latest reorganization of the VNMC.