[rpdillon]

An important point here is that there are both legal and illegal orders. Military personnel are instructed obey every legal order, and disobey every illegal order (at least I was).

In the military, we have the UCMJ that allows us to prosecute those military personnel that issue illegal orders. The President is the Commander-in-Chief, but he is a civilian, so the UCMJ doesn't apply. I always thought he would be charged under criminal law in that case, but it seems that this ruling precludes that.

[saucetenuto]

This is true but I don't think it meaningfully checks the president, because the pardon power is also absolute and unreviewable, and does cover courts martial (as we saw in the Eddie Gallagher case). Military personnel are not required to follow illegal orders from the president, but if they do they won't face legal sanction.