With a corrupt legal system, they don't need nothing. Picture a Roger Stone type arrest with heavily armed troops, armored vehicles, and Trump being dragged out in the middle of the night in front of CNN camera crews who had been tipped off. All of it shown in the propaganda media including his processing into a jail. They could do that and more if they feel threatened by President Trump.
Yep. They could arrest Trump. It would make him a martyr. It would make him stronger. I can imagine the demonstrations and riots to follow. It would push us to the edge of civil war if not over.