There’s a lot of debate taking place over precisely what Supreme Court Chief Justice John Roberts’ role will be in the impeachment trial that kicks off in full gear today. I suppose that’s understandable since the only mention made of this matter in the Constitution simply says, “When the President of the United States is tried, the Chief Justice shall preside.” Sadly, this leaves a lot of room for interpretation over precisely what “preside” means in this context.

One of the key questions that will need to be tackled first is what sort of rulings Roberts is allowed to make. The first bone of contention is over the question of calling witnesses. While the GOP majority seems to want that handled by a vote, the Democrats would like Roberts to step in and rule that witnesses will be allowed. But the Senate Republicans are warning that if Roberts does that, he may have to recuse himself from any future cases where the President claims executive privilege regarding testimony from such witnesses. (The Hill)

Senate Democrats are pressing Chief Justice John Roberts to rule in favor of calling witnesses at President Trump’s impeachment trial, while Republicans argue it could force his recusal from potential Supreme Court cases.

Democrats say it’s simple: A trial can’t be a fair one without witnesses. Republicans counter that if Roberts rules on witnesses, he will have to recuse himself from any Supreme Court case on Trump’s claims of executive privilege over potential witnesses like former national security adviser John Bolton and acting White House chief of staff Mick Mulvaney.

It seems to me that the Senate majority is shooting themselves in the foot with this argument. (Or at least undermining the President.) There very well may be future cases involving Trump’s claims to executive privilege since the Democrats and their surrogates are constantly suing him over one thing or another. And if those cases wind up being appealed to the Supreme Court, Trump will need all the votes he can get.

There’s also a question as to whether or not Roberts gets to cast a vote to break ties on matters that he sends to the floor for a vote. That might sound curious to some, but there’s actually precedent for it. During the impeachment trial of Andrew Johnson, Chief Justice Salmon P. Chase broke two ties regarding procedural matters by casting a vote. (As The Hill points out, one of those votes was a question as to whether or not he could vote to break ties.)

Normally, the Vice President would break any tie vote in the Senate, but that generally only happens when he is called in to preside as the President of the Senate after a tie occurs. As far as the final impeachment vote goes, a two-thirds majority is required to convict, so a tie isn’t possible. But for setting the rules and deciding procedural matters (such as the rules for calling witnesses) we could easily see a tie happen. With Roberts presiding instead of the VP, would that apply? Or does Roberts inherit the Vice President’s vote?

The other alternative, as some are arguing, is that there is no tie-breaking vote available and a tie simply results in the measure failing because they didn’t come up with 51 votes. Or at least that’s the approach that Lisa Murkowski (among others) seems to be taking.

These are all good questions. And as we’ve discussed here before, we’re stuck in a gray area largely because the Founders didn’t bother to provide many (or any) specifics as to how an impeachment trial is supposed to run. They left it up to the members of the Senate to decide when writing their own rules.