This time he really means business. Gates sounded the death knell for U.S. Joint Forces command at the beginning of the week and by the end of the week he had his sites trained on the Marine Corps. In a speech at the Marines’ Memorial Club and Hotel in San Francisco on Thursday, he ordered a thorough force structure review of the Marine Corps. It’s no news that the Corps is prepared to draw down its personnel after operations in Afghanistan wind down. But this goes deeper. He said he wants to determine what an expeditionary force in readiness should…