The Constitution is 100% clear that only Congress has the power to decide an impeachment case. But the President is a moron who neither reads nor understands the Constitution. And so when the President makes some obviously dumb claim about how the process works, Republicans will adopt his dumb opinion as their own. That includes the Republicans who barely pretend anymore to be non-partisan Justices on the Supreme Court. So I think there is actually a danger that 5 Justices would adopt this stupid theory and make up some weird Supreme Court appeal process in the unlikely event that the Senate convicted Trump in the impeachment case.
