Actually, that's not true. If it was, then the military would have to prove the lawfulness of every single order it gave whenever someone disagreed with one.
That's why the presumption is actually that the order is lawful, and so the challenger has to prove that it isn't.
And before he can do that, he has to show that there is enough doubt to allow him to make his argument.
And before he does that, he has to show that he challenged the order in a lawful way, so that he can be allowed to show his doubt.
Personally, I think he's right. But the military is not constructed so as to make successfully challenging orders easy.
Then, oaths are a sham.
Personally, I think he’s right.
Agreed — but he’s screwed.
There's the rub. Will he be allowed to show his evidence?