Once he has the full might of the Feudal Federal Government behind him, it may be practically impossible, although it will always be a theoretical possibility.
Oh, you say there is a clause in Article III of the Constitution prohibiting that? Well let's ignore it. Let the judges sue. Who will be able to hear the case and not have a conflict of interest?
Or perhaps we can simply pass a bill in Congress declaring the judges to be criminals and sentencing them to death. A prohibition against bills of attainder? Let's ignore that one, too. It was written by a bunch of dead white men 200 years ago. You don't really expect us to take that stuff seriously, do you?