Once a Marine, Always a Marine:
Once the title "U.S. Marine" has been earned, it is retained. There are no ex-Marines or former-Marines. There are (1) active duty Marines, (2) retired Marines, (3) reserve Marines, and (4) Marine veterans. Nonetheless, once one has earned the title, he remains a Marine for life.
"You earned the title "Marine" upon graduation from boot recruit training. It wasn't willed to you; it isn't a gift. It is not a government subsidy. Few can claim the title; no one can take it away. It is yours forever." Tom Barlett - Leatherneck Magazine