For the second time, President Donald Trump has been impeached. It will now be up to the Senate to convict or acquit Trump, but a Senate vote probably won't happen until after Jan. 20, when President-elect Joe Biden takes office. Harvard law professor and constitutional scholar Noah Feldman discussed Trump's second impeachment with GBH All Things Considered host Arun Rath. This transcript has been edited for clarity.

Arun Rath: This was a bipartisan impeachment, with 10 Republicans siding with Democrats and voting to impeach. Things did not go that way with Trump's first impeachment. Give us a bit of historical context, because this is historically bipartisan, right?

Noah Feldman: It is. President Andrew Johnson's impeachment effort was down pretty close to exact party lines, and more Republicans voted now to impeach Trump than Democrats voted to impeach former President Bill Clinton. So counting only those impeachments that have actually gone to a vote, and excluding President Richard Nixon's potential impeachment, which I'm sure would also have been very bipartisan, this is the most bipartisan impeachment thus far.

Rath: To refresh people's memory, with Nixon, it didn't get to that point because he saw where the votes were heading.

Feldman: He saw the writing on the wall, and he resigned before he could be impeached. Back in those days, being impeached was itself thought to be such a shame that it would be a reason to walk away. Today, apparently, you can do it twice.

Rath: How times have changed. Was there anything about today's proceedings that surprised you?

Feldman: The surprise really lies in the shocking conduct that gave rise to the impeachment. I mean, just to take a deep breath and realize that the president of the United States, the sitting president, urged a crowd to march on the Capitol to stop them from "stealing" the election, when what they were actually doing in Congress was counting the votes to declare his opponent to be president. And then the crowd actually did that. I mean, that's just so astonishing that it should not escape our attention, even though we've been so in the news cycle that it's maybe starting to seem normal to us.

The other thing is just the incredible speed of this process. Republicans will say it was too fast. Of course, the speed was driven by the very short time that Trump has left in office. Republicans said that the last impeachment went too quickly, and if they thought that went too quickly, they really are going to think this went too quickly. But the reality is it was unprecedented for an article of impeachment to be drawn up so quickly and voted on so quickly. That's also an important part of the historical record here.

Rath: In terms of the constitutional context of this, is impeachment the best remedy for something that I think maybe none of the framers would have anticipated?

Feldman: I think it is. The 25th Amendment is really about a president who is "unable to discharge" the duties of the office. Trump is not unable, he's just doing it horribly and unlawfully, and so I don't really think the 25th Amendment was a good fit. Impeachment is the remedy that the framers put in place for a president who subverts the democratic process, and that's what this was. Call it by any name you wish. Call it incitement to insurrection, which is what the article of impeachment calls it, or just call it subverting democracy. The framers understood that such a president had to be removed, and they thought that this was the appropriate process for doing so. Perhaps most significantly for our purposes, they left also the option post-impeachment of a vote to block that person from ever holding office again, and that's going to be highly relevant here.

Rath: I want to talk about that. But first, I want to spend a moment talking about the members of Congress who sided with Trump — and, one could say, sided with the mob in trying to overturn the election, what's been termed now the "sedition caucus" — people like Republican Sens. Ted Cruz of Texas and Josh Hawley of Missouri. There have been calls to censure them, to even expel them from the Senate. Is that something that would be viable? Are there options that would be on the table, and could we see them carried out?

Feldman: The Senate can issue any censure that it wants. That's up to the judgment of the senators. That's of course a possibility. Removal, expulsion, typically has in Senate precedent required much more concrete wrongdoing. It's also important to note that the Constitution itself says that members of Congress, including senators, can't be held responsible "in any other place" — that is, outside of Congress — for anything they say in the midst of a debate on the floor of Congress. Did those senators incite the crowd in the same way that Donald Trump did? Perhaps, but not in exactly the same way. They didn't literally address the crowd, because they were inside of the Senate doing their part from there. So I think expulsion is pretty unlikely to happen in practical terms.

Rath: Let's talk about what happens when this does get to the Senate. You mentioned that one of the things that does make this relevant, and not just a show exercise for a president who would be out of office at that point, would be the possibility of barring him from holding federal office ever again. Talk about that. Is that something that comes automatically with impeachment? How would that work?

Feldman: No, it doesn't come automatically. It's a two-stage process. First, the Senate would have to convict — then he will no longer be the president, presumably — but they would have to convict Donald Trump of high crimes and misdemeanors in a two-thirds vote. Then after that, there would be a second vote, which interestingly would only be a majority vote to remove him permanently from ever holding the office of the president. That is to say, even if he's no longer president, they can block him from ever serving again, and that only takes a majority. So that would be the two-step process. It's important to note they can't skip the first step. They can't just vote that he can't ever serve in office again without previously convicting him by two-thirds.

Rath: There have been some who have suggested that this actually would not be proper or constitutional, to do this after he is out of office. Would that be something that could go to the Supreme Court for a decision?

Feldman: I think it probably won't go to the Supreme Court. To be sure, there are two plausible views here. One view says, the Constitution talks about an incumbent president being put up for impeachment. And he'll no longer be the incumbent, so therefore you can't impeach him. There is an added argument there that in the U.S. system, we can only impeach government officials. We can't impeach just anybody, which they actually were able to do in the old English form of impeachment.

The counterview says, well, look, he was the president, and he's being impeached for high crimes and misdemeanors that he committed while he was the president, and there's a practical difference — namely, whether he can be removed from office. And so we should be able to go forward. That side likes to quote John Quincy Adams, who when he was in Congress, having previously been president said, 'I believe that I can be impeached as long as I have breath in me for anything that I've done as part of government.' So that's some vague precedent, but it's of course never happened.

The reality is that when something like this has never happened, it will be up to the Senate to decide, and it won't get brought to the courts. If it were, I don't think the courts would listen to it. It's a kind of question that's squarely in the hands of the senators. So they'll vote on it, and it'll depend what a majority of the Senate has to say as to whether this trial can go forward after Donald Trump is no longer president. If the Democrats have a majority in the Senate, as they now will with Kamala Harris as the deciding vote, they could go forward with the trial if they choose to.