For extraordinary heroism while serving as a Platoon Sergeant of Company F Second Battalion, Fifth Marines, First Marine Division (Reinforced), in action against enemy aggressor forces in Korea on 17 August 1952. When a friendly patrol, in route to a forward combat outpost, suffered heavy casualties and was unable to effect a withdrawal during a surprise attack by a well-entrenched and cleverly concealed enemy force, Staff Sergeant Louder skillfully maneuvered a relief unit of ten Marines through intense hostile mortar and artillery fire to the vicinity of the casualties. With his own unit pinned down by a withering hail of small-arms fire, he expertly deployed his men to positions where fire superiority could be established and, in company with one other man, attempted to assault the hostile position. When his comrade sustained painful wounds and was forced to withdraw, Staff Sergeant Louder continued the assault alone, worked his way up the hill and into the hostile trenches and, firing his weapon with deadly accuracy succeeded in forcing the enemy back and in silencing all hostile small-arms fire, thereby enabling the remainder of his unit to move forward and successfully evacuate the casualties. By his valiant leadership, indomitable fighting spirit and resolute determination in the face of intense enemy opposition, Staff Sergeant Louder served to inspire all who observed him and upheld the highest traditions of the United States Naval Service.