The principle is "military obedience to civilian authority".
The chain of command is president-secretary of defense-chairman of the joint chiefs, etc., down to this guy. Our disgusting and despicable congress just passed a law creating this appalling situation, which has surely been signed into law by our equally disgusting and despicable president.
The Commandant of the Marine Corps has three choices: 1) pretend it's an illegal order and refuse to obey; 2) resign and lambaste congress and obummer for their crap; 3) act like a Marine and do his best to follow orders.
He's doing #3. Leadership implies followership, even if you don't like the orders.
Why should leadership *always* imply followership? What kind of mindless automaton are you? Those kind of marines are not to be respected...they are to be feared.