The January 6 hearings opened the door to an almost historically unheard-of event: The possibility of criminal charges against a former U.S. president. For former President Trump to be charged, the House Select Committee investigating the Capitol breach would have to find compelling evidence for seditious conspiracy. Daniel Medwed, GBH News legal analyst and Northeastern University law professor, joined GBH’s Morning Edition hosts Paris Alston and Jeremy Siegel to explain the legal standards involved. This transcript has been edited for clarity and length.

Paris Alston: The House Select Committee on the January 6 Insurrection has wrapped its second of seven public hearings on the events of that day. During the first two hearings, the panel laid the groundwork for establishing that former President Trump played a pivotal role in the attack on the Capitol building.

So far the hearings have revealed new information and footage that shed light on former President Trump's involvement in the insurrection. Do you think the evidence presented provides the basis for potential criminal charges here?

Daniel Medwed: I think it's a little premature. It remains to be seen exactly what will be established, because we're at the early stages of this process. But it certainly, as you pointed out, has laid the groundwork for some potential criminal charges here. Specifically, the evidence reveals that Trump persisted in his false claims of voter fraud even after several of his closest advisers, including former Attorney General Bill Barr — I found that especially riveting — assured him that there was no such evidence, and that he continued to egg on his supporters to take decisive action to "stop the steal."

Now, it's important to note that the committee itself doesn't have the authority to file criminal charges. What the committee would do would be to refer the case to the Department of Justice, and then DOJ would make that determination. And of course, whether DOJ actually makes that determination or not involves a number of practical and political variables that make it pretty hard to predict at this stage. But I think there is the basis for some charges here.

Jeremy Siegel: So if something like that were to move forward, if the former president were charged, what might the specific crime or crimes be?

Medwed: They could be the crimes of obstruction of an official proceeding and also something known as seditious conspiracy. Let me explain — clearly the committee is trying to establish some type of direct link between some activities of white supremacists on January 6 and those of President Trump that day. And earlier this year, 14 members of the Proud Boys and the Oath Keepers were charged with a variety of crimes, including obstruction of an official proceeding and seditious conspiracy. Seditious conspiracy in particular is a very serious federal charge. It's punishable by up to 20 years in prison. And the gist of it is this idea of fomenting rebellion.

The particular charge against these defendants is that two or more of them knowingly conspired to use violence to prevent or hinder the execution of federal law. That's that sort of fancy legalese that basically says they were trying to stop the peaceful transfer of power after a valid presidential election. And it seems like the committee is trying to connect the dots and suggest that Trump may have been part of this conspiracy.

Alston: To tie him to this seditious conspiracy, would prosecutors need to show a direct link between him and, say, a leader of the Proud Boys or the Oath Keepers? For instance, maybe a telephone call or some other conversation in which they coordinated their behavior around this?

"It seems like the committee is trying to connect the dots and suggest that Trump may have been part of this conspiracy."

Medwed: That's so interesting. Not necessarily, and here's why: The hallmark of a conspiracy is an agreement. And most criminal co-conspirators obviously don't reduce their agreement to writing. There's not a contract about their criminal objectives, and it's usually not even explicit or expressed through sort of oral communication either. For that reason, much of the case law in this area suggests that a tacit or implicit understanding is enough to rise to the level of an agreement for conspiracy law.

I think that's why the committee took such pains to show Trump's tweets and also his infamous, notorious comment during one of the debates with President Biden, in which he told the Proud Boys to "stand back and stand by." I think the goal there was to suggest that there was some type of wink-and-a-nod-arrangement, some type of implied tacit understanding that they would coordinate their efforts to overturn the election. So I think that the agreement won't necessarily be easy to prove, but it's maybe not as difficult as it would appear at first glance.

Siegel: It's interesting thinking about the legal implications here, because I'm thinking back to a conversation our friends at Boston Public Radio had about the point of airing some of this during primetime and how people viewing might not have their minds changed about that day. But when you think about the legal effects of it, this could be huge if there are charges. So sticking with this seditious conspiracy, what else, beyond an agreement like you were just talking about, would prosecutors need to show to charge Trump?

Medwed: There are typically two other elements, at least. So first, you have to show that one or more of the co-conspirators took an act in furtherance of the conspiratorial objective. If you were just to criminalize people for an agreement, it would be a little bit like punishing people for thoughts, for their intentions. So you have to act on your thoughts, you have to do something, even if only a baby step in pursuit of a conspiracy. That shouldn't be a problem here, given what the Proud Boys and the Oath Keepers did on that day, on January 6. The second element might be trickier. Prosecutors would have to prove that Trump had a culpable mental state, that he acted intentionally or knowingly when he conspired with these other people to use violence to change the election results. That might be a little harder to prove.

"If you were just to criminalize people for an agreement, it would be a little bit like punishing people for thoughts ... you have to act on your thoughts, even if only a baby step in pursuit of a conspiracy."

Alston: Are you essentially saying that Trump could claim that even if there was this implicit agreement to dispute the election results, he didn't intend or maybe didn't know, that the Oath Keepers or Proud Boys would take it that far?

Medwed: Exactly. That's probably going to be his defense. It's known as the other minds defense in criminal law, and the idea is, it's entirely subjective to the defendant. What did he intend? What did he know? And it's pretty common for defendants to make that argument.

Siegel: How do you go about proving knowledge under that type of test? Wouldn't every criminal defendant claim they don't know what's going on here?

Medwed: Exactly. Plausible deniability. "I didn't intend for this to happen" or "I didn't know that they would do this." Absolutely. Here's how prosecutors tend to deal with that conundrum, which comes up in many, many cases. It really is, as I alluded to before, known as the other minds problem. How do you prove what's going on in someone else's mind, the defendant's mind?

Here's how it works. On the one hand, what the defendant is saying about their intent, that's direct evidence. And you don't necessarily have to accept it at face value. Because, Jeremy, as you point out, there's an incentive for defendants to say, "I didn't have this intent, I didn't have this knowledge." So on the other hand, what prosecutors look to is the circumstantial evidence, not what the defendant says they believed, but what did the defendant do? What were their actions and what is the fair inference from their words? And here, when you look at former President Trump's actions and his words, there is an inference that he perhaps knew or intended to push the Proud Boys and the Oath Keepers to act in this fashion. At least that's possible. That's something that prosecutors might eventually try to prove.