Think of it like a whole bunch of people standing around a $100 bill left on the ground. Everybody’s standing around waiting for the legitimate owner to come by and pick it up. Trump doesn’t give a shit about that. He’s gonna walk by, shove everyone aside, and grab it. When everyone else tries to stop him and say the money isn’t his, he’s just going to look at you and say “Who’s is it, and why haven’t they picked it up yet?” And while everybody else is standing around trying to figure out the answer to that, Trump is walking away with the money and saying “Finders keepers, asshole. It’s mine now”. Even if the original owner shows up later and tries to lay claim to the money, he’d have to prove that that specific $100 bill was his to begin with or the judge is just going to say that it’s Trump’s money now.

Think that, except with the power of the US government instead of a c-note. And Trump is hoping that the courts will use the same logic: since nobody else tried to claim the power before, and there’s nothing explicitly granting those powers to someone else, Trump is hoping that the courts will just let him keep those powers in a twisted form of finders-keepers. And given this court system, he very well might win.