Before leaving office, former president Donald Trump issued pardons and commuted the sentences of nearly 150 people, including political allies like Steve Bannon. GBH Morning Edition host Joe Mathieu spoke with Northeastern University law professor and GBH News legal analyst Daniel Medwed to learn more about how the clemency process works at the federal and state levels, and why it hasn't been used in Massachusetts since 2015. The transcript below has been edited for clarity.

Joe Mathieu: We've talked about pardon powers before here, especially after some earlier controversial clemency grants by Trump. But in terms of the basics, how does it work at the federal level before we move any further?

Daniel Medwed: So here's the overview. The Constitution vests the president and the president alone with this power to extend mercy, often called clemency, to people convicted of all federal crimes except for impeachment. This function covers a few different things, not just the classic pardon power, which is when you forgive someone for a crime and wipe their slate clean, but also the power to commute a sentence to basically lop off the remaining prison term, but keep the conviction nominally on the books. Now, even though the president holds this power alone under the Constitution, the Department of Justice has evolved into a very important supportive role where it defines eligibility criteria, fields requests for pardons and basically makes recommendations to the president.

Mathieu: So let's talk about Massachusetts, Daniel. This has come up a couple of times. People wonder what happens on the state level. How does Governor Baker, for instance, pardon someone?

Medwed: Well, it's interesting. On the one hand, at least superficially, it's somewhat similar to the federal model. They both follow this hybrid model where a chief executive and an administrative body share the responsibility. So in Massachusetts, there's interplay between the governor and the Governor's Council and the state parole board. But on the other hand when you dig deeper, Joe, there's a bleak, very important difference. So the federal Constitution, as I noted, vests this power exclusively in the president, which means he can bypass [the] DOJ as he sees fit. We saw this dramatically last week all those stories about people approaching Trump directly or through intermediaries and basically cutting the Department of Justice out of the process. That couldn't happen in Massachusetts because the governor's power in this area is limited by Article 73 of our Constitution. It requires that any clemency grant must be, "by and with the advice" of Council. So the Governor's Council plays a constitutionally mandatory role and the Massachusetts parole board plays more of an advisory role.

Mathieu: What's the practical effect of these limitations here, Daniel? Do they lead to better decisions?

Medwed: In theory, yes, based on the idea that more heads are better than one and that there are these standards in place. But in practice, Massachusetts is one of the stingiest states across the nation when it comes to pardons. This trend is really dramatic when you look at the last 20 years. Mitt Romney didn't issue a single pardon when he was governor. And one of our most progressive governors, Deval Patrick, only issued a handful I believe six pardons and one commutation over the course of his eight years in office and they all occurred at the tail end in 2014 and 2015. These numbers really pale in comparison to other states, including our neighbor, Connecticut, which granted more than 700 pardons just in 2018.

Mathieu: Wow. And Governor Baker hasn't issued any, right?

Medwed: Not a single pardon or commutation since he assumed office in 2015. Though, to be fair, he hasn't had many opportunities. The parole board hasn't recommended many to him. That could change because earlier this month, the board made a formal recommendation to commute the sentence of a man named Thomas Koonce, a former Marine who was home on leave. He had no criminal record when he shot and killed a man in New Bedford while fleeing the area. He always accepted responsibility for this crime, though he claimed it was an accident and developed an exemplary record behind bars. Right now, the governor is considering it and he might sign off on it subject to the blessing of the Governor's Council. If he does, I hope it could open the door to more of these.