OK...here’s the oath: “I, _____, 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.” (Title 10, US Code; Act of 5 May 1960 replacing the wording first adopted in 1789, with amendment effective 5 October 1962).
The key in the oath concerning this Marine is “I will obey the orders of the President of the United States”. Unless Congress says otherwise, I believe all his orders are lawful.
Apparently, the problem is calling attention to the fact (again) that this President is a crook, a commie thug, and is fully agreeable with declaring martial law in order to facilitate the intentions of his handlers. This marine is nothing to the president, or the pentagon, and his career and/or life are trivial in comparison to the wants of our thief-in-chief.