Major Mari received the Distinguished Service Cross in recognition of his extraordinary heroism during the period 9-12 March 1966 while serving as a first lieutenant and executive officer at Camp A Shau, Republic of Vietnam. When the camp was attacked by a large Viet Cong force, the then First Lieutenant Mari ran through 200 Meters of intense hostile fire to his battle positions where he organized and directed the confused and stunned Vietnamese until they repelled the attacking Viet Cong. Later in the day, First Lieutenant Mari directed a detail to secure and cover an airstrip for two L-19 and aircraft to land and evacuate a seriously wounded American. When the Viet Cong launched their main attack with two reinforced battalions, First Lieutenant Mari began to provide an effective firing line until the Viet Cong broke into the camp from the rear. He immediately formed a perimeter and held his position until he was forced to withdraw to a different location. Observing a large force of Viet Cong massing for an attack on the communications bunker, he and another American boldly fought off the advancing insurgents with machine gun fire. When the Viet Cong destroyed his gun and killed his comrade along with several Vietnamese, he quickly exited the bunker and led a small force in a counter attack. When the overwhelming Viet Cong halted their attack, First Lieutenant Mari skillfully deployed a small force, broke up the Viet Cong assault on the bunker, and drove them back with heavy casualties. After repeated attacks by the large Viet Cong force and upon being ordered to evacuate the area. First Lieutenant Mari destroyed the radios and classified documents and prepared the men for evacuation. He then led some troops through 500 meters of intense hostile fire to a landing zone and fought a delaying action until all of the defenders had cleared the camp. First Lieutenant Mari continued to evade the Viet Cong and direct the evacuation of his men for several days until he was finally rescued by a helicopter. His extraordinary heroism in close combat against a numerically superior hostile force was in keeping with the highest traditions of the military service and reflects great credit upon himself, his unit, and the United Sates Army.

MAJ. Mari joined the Legion of Valor in 1974 as a life member.