Started a new thread on it. The Constitution doesn't define the rules the House or Senate has to follow. They do. So it means they can change them which allows quite a lot of power to any party with a majority in either body. The SCOTUS would be there to ensure whatever permanently codified rules are enforced, making decisions on whether witnesses are material, evidence reaches whatever agreed upon standard to be presented, resolving promptly decisions regarding privilege, etc., so there isn't the issues going through a laborious legal process. Those kinds of things.