For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty. When the company was suddenly pinned down by a hail of extremely accurate enemy fire and was quickly separated from the remainder of the battalion by over 500 meters of open and fire-swept ground and casualties mounted rapidly, Lt. Barnum quickly made a hazardous reconnaissance of the area, seeking targets for his artillery. Finding the rifle company commander mortally wounded and the radio operator killed, he, with complete disregard for his safety, gave aid to the dying commander, then removed the radio from the dead operator and strapped it to himself. He immediately assumed command of the rifle company, and moving at once into the midst of the heavy fire, rallying and giving encouragement to all units, reorganizing them to replace the loss of key personnel and lead their attack on enemy positions from which deadly fire continued to come. His sound and swift decisions and his obvious calm served to stabilize the badly decimated units and his gallant example as he stood exposed repeatedly to point out targets served as an inspiration to all. Provided with two armed helicopters, he moved fearlessly through enemy fire to control the air attacks against the firmly entrenched enemy while skillfully directing one platoon in a successful counterattack on the key enemy positions. Having thus cleared a small area, he requested and directed the landing of two transport helicopters for the evacuation of the dead and wounded. He then assisted in the mopping-up and final seizure of the battalion's objective. His gallant initiative and heroic conduct reflected great credit upon himself and were in keeping with the highest traditions of the Marine Corps and the U.S. Naval Service.