The danger is that they will imprison or execute one innocent person.
All it takes is one.
That would send a chill down the spine of many that would want to speak up but are fearful for their lives and their freedom.
That is why Mark Kelly is to be commended for standing up for "free speech". That is really what it is all about. The First Amendment is under threat. Speaking the truth can be turned into a lie with the right propagandists carving around the edges.
No one can think of any President disputing the fact that all troops should follow legal orders. They should not follow "illegal orders". Are we to believe that all orders from the President are legal, no matter what? Shoot them in the legs? Kill those innocent people in the boat? They might be drug smugglers? Does he believe he has the right to have Seal Team Six assassinate his political opponents? Obviously, he does.
So, it is entirely appropriate for members of Congress to remind members of the military of their oath to the Constitution. Trump is using the issue to divide the military even as we speak. We could use a uniting message from the Joint Chiefs of Staff to clarify the situation, in my opinion.