Background: Marion Gordon "Pat" Robertson (born March 22, 1930) is an American media mogul, executive chairman, politician, and former Southern Baptist minister who advocates a conservative Christian ideology. He presently serves as chancellor and CEO of Regent University and chairman of the Christian Broadcasting Network. Spanning over five decades, Robertson has a career as the founder of several major organizations and corporations as well as a university: The Christian Broadcasting Network (CBN), the International Family Entertainment Inc. (ABC Family Channel), Regent University, the American Center for Law & Justice (ACLJ), the Founders Inn and Conference Center, the Christian Coalition, an L-1011 Flying Hospital, Operation Blessing International Relief and Development Corporation, and CBN Asia. He is a best-selling author and the host of The 700 Club, a Christian News and TV program broadcast live weekdays on Freeform (formerly ABC Family) via satellite from CBN studios, as well as on channels throughout the United States, and on CBN network affiliates worldwide.
Context: When he was eleven, Robertson was enrolled in the preparatory McDonogh School outside Baltimore, Maryland. From 1940 until 1946 he attended The McCallie School in Chattanooga, Tennessee, where he graduated with honors. He gained admission to Washington and Lee University, where he received a B.A. in History, graduating magna cum laude. He joined Sigma Alpha Epsilon fraternity. Robertson has said, "Although I worked hard at my studies, my real major centered around lovely young ladies who attended the nearby girls schools."  In 1948, the draft was reinstated and Robertson was given the option of joining the Marine Corps or being drafted into the Army; he opted for the first.  In his words, "We did long, grueling marches to toughen the men, plus refresher training in firearms and bayonet combat." In the same year, he transferred to Korea, "I ended up at the headquarters command of the First Marine Division," says Robertson. "The Division was in combat in the hot and dusty, then bitterly cold portion of North Korea just above the 38th Parallel later identified as the 'Punchbowl' and 'Heartbreak Ridge.' For that service in the Korean War, the Marine Corps awarded me three battle stars for 'action against the enemy.'"  However, former Republican Congressman Paul "Pete" McCloskey, Jr., who served with Robertson in Korea, wrote a public letter which said that Robertson was actually spared combat duty when his powerful father, a U.S. Senator, intervened on his behalf, and that Robertson spent most of his time in an office in Japan. According to McCloskey, his time in the service was not in combat but as the "liquor officer" responsible for keeping the officers' clubs supplied with alcohol. Robertson filed a $35 million libel suit against McCloskey in 1986. He dropped the case in 1988, before it came to trial and paid McCloskey's court costs. According to a newspaper report from 1986, Robertson confirmed elements of McCloskey's allegations and said that he never saw front-line duty.  Robertson was promoted to First Lieutenant in 1952 upon his return to the United States. He then went on to receive a law degree from Yale Law School in 1955, near the top of his class. However, he failed his first and only attempt at the New York bar exam. Shortly thereafter he underwent a religious conversion, and decided against pursuing a career in law. Instead, Robertson attended The Biblical Seminary in New York, where he received a Master of Divinity degree in 1959.
Question: When did he leave the military service?. Whats the answer?
Robertson was promoted to First Lieutenant in 1952 upon his return to the United States. He then went on to receive a law degree from Yale Law School in 1955,