 Complete the following phrase:  Cowan was born in Sacramento, California. He enlisted in the United States Navy at the age of 17, received an appointment to and graduated from the U.S. Naval Academy in 1966, and was commissioned as a lieutet the United States Marine Corps. He subsequently spent three and a half years in Vietnam. On his first tour he served as a platoon commander with the 3rd Battalion, 26th Marines, along the DMZ and at the 