> The dissents overlook the more likely prospect of an Executive Branch that cannibalizes itself, with each successive President free to prosecute his predecessors, yet unable to boldly and fearlessly carry out his duties for fear that he may be next. ... Virtually every President is criticized for insufficiently enforcing some aspect of federal law (such as drug, gun, immigration, or environmental laws). An enterprising prosecutor in a new administration may assert that a previous President violated that broad statute. Without immunity, such types of prosecutions of ex-Presidents could quickly become routine.
Their argument isn't that it's not likely, it's that there's another failure mode that is even more likely.
