It’s all negotiable, decided by a simple Senate majority (if all are present, 50 + VP). Still, as I have maintained steadfastly, this House will never even hold an actual up-or-down impeachment vote.
There is no "ad litem" in the Constitution, but that is countered by the fact that there is no "Chief Justice" in Article III, which creates the Supreme Court.
The office of a "Chief Justice" has been in existence since the first Supreme Court (John Jay), but I don't think the Framers meant the Chief Justice to be a mutable, situational office. Every Chief Justice in the history of the nation either resigned, retired, or died in office.
I suppose a progressive could say that there's always a first time, but why MUST there be a first time, and why MUST that first time be now (when it suits the Democrats and hurts the Republicans)? If there must be a first time, wouldn't We the People expect it to be at a time when the nation's forward path is not at stake, like with some routine case that reaches the highest court?
So, for me, I think there are some questions I'd need answered before I can resolve this question:
-PJ