The question to follow every “x can’t do y, it’s illegal” with is “ok, what happens if he does it”
For most of us it’s “the cops will come and maybe kill you”
For the guys running things it’s “a strongly worded letter will be sent”
"Illegal" doesn't mean "impossible."
Every day, people say "but Trump can't do that! That's illegal!"
Of course he can do that. Police can ignore your rights. Judges can ignore the law. People speed every single day. Laws are lists of consequences: nothing more.