Oath of Enlistment

"I, (Name), do solemnly swear (or affirm) that I will support and defend
the Constitution of the United States against all enemies, foreign and
domestic; that I will bear true faith and allegiance to the same; and
that I will obey the orders of the President of the United States and
the orders of the officers appointed over me, according to regulations
and the Uniform Code of Military Justice. So help me God."

This Marine could have expressed his views and even shared his
frustrations with friends or a counselor in the Marine Corps. Where he
crossed the line was when he said how would not follow the orders of the
Commander and Chief. He swore in and gave his oath, and he surely knew
better.

Please read more here-
http://news.yahoo.com/marine-argue-free-speech-case-hearing-084156859.html