The ideal from Trump's pov is being able to deport US citizens to El Salvador... without due process. Until he can do that he can only pretend to be king. He's slowly shifting the Overton window [1] in that direction.
Due process doesn't exist just to let sneaky criminals make all their sneaky little arguments like "there is no evidence I committed a crime." It also exists to establish basic facts like "what is this person's name?"