Captain Christopher J. O’Sullivan, Infantry, United States Army: For extraordinary heroism in connection with military operations involving an armed hostile force. On 19 April 1965, Captain O’Sullivan was serving as Senior Advisor to the 39th Ranger Battalion, Army of the Republic of Vietnam, which was participating in a search and destroy mission in connection with Operation Quyet Thang 518. During the operation, the Ranger Battalion as the lead element of a northern force moved west on one axis while another battalion of Vietnamese Marines and armored personnel carriers, which composed the southern force, also moved west on another axis. At 1700 hours, the composite battalion was attacked by a strong Viet Cong force and was forced to withdraw towards the 39th Range Battalion. During the initial contact of the friendly forces, Captain O’Sullivan, realizing the importance of command control, attempted to stop the withdrawing troops and establish a defensive line to hold back the attacking insurgents. However, due to the heavy concentration of insurgent fire, his attempt proved futile and the friendly forces were forced to withdraw to another defensive position approximately four hundred meters to the rear of the first line. Upon establishing this hasty defense, Captain O’Sullivan, with complete disregard for his personal safety, continuously exposed himself to the hostile fire and moved from one position to another to effectively direct a hail of deadly fire upon the advancing insurgents. During the ensuing battle, Captain O’Sullivan personally accounted for fifteen Viet Cong casualties and as a result of his dynamic leadership and heroic actions, seventy five troops which were pinned down and trapped by the Viet Cong were rescued. Captain O’Sullivan extraordinary heroism and gallantry in action were in keeping with the highest traditions of the United States Army and reflect great credit upon himself and the military service.