If the US government has proof that Bradley Manning consciously "aided the enemy" then they should charge him with treason.
American Constitution, Article 3 Section 3Treason against the United States, shall consist only in levying war against them, or in adhering to their enemies, giving them aid and comfort. No person shall be convicted of treason unless on the testimony of two witnesses to the same overt act, or on confession in open court.The Congress shall have power to declare the punishment of treason, but no attainder of treason shall work corruption of blood, or forfeiture except during the life of the person attainted.
So if Manning has adhered to America's enemies, "giving them aid and comfort," he should be charged with treason. He hasn't.
On the other hand, his Oath of Enlistment reads:
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.
The Constitution is silent about the consequences of disobeying military orders in order to support and defend the the Constitution of the United States.
We're back to :
Testimony July 16, 1973, by former Major Hal Knight, USAF, at Hearings of the Senate Armed Services Committee, Ninety-Third Congress, on bombing in Cambodia - particularly regarding falsification of records of B52 targets - page 44
Mr. Knight. Frankly, sir, I felt that the Senate Armed Services Committee was deceived. On this side of the House, if you go up through the military chain, I don't imagine that anybody was deceived.
Senator Thurmond. It was your duty to act within the military channel and to pass on anything to higher headquarters which you felt was improper, wasn't it?
Mr. Knight. Yes, sir, but I didn't take an oath to support the military, I took an oath to support and defend the Constitution. That goes beyond strictly military channels.