>As for SEAL Team 6, they have a "duty to disobey" unlawful orders[1]-- which every member of the team probably knows off the top of their heads-- and which is a much more effective real-time check on a president's authority.

Now, let's play that out in real time:

Donald Trump: please kill person XYZ. Seal Team 6: Uh, no sir, that's illegal. We cannot do that. Donald Trump: the courts say I have immunity, this is an official act. Person XYZ is a threat to our country, and under the constitution I'm allowed to defend this country against all enemies, foreign and domestic. This person is a domestic enemy. Kill them. Seal Team 6: Uh, no sir, we can't do that. Donald Trump: You're fired. I'm replacing you with someone that can do what I tell them. Seal team 6: Ok, we'll kill person XYZ.

And the courts will have no problem with that, as per their ruling.