Supreme Judicial Court Judge Frank Gazianohas sided with Suffolk County District Attorney Rachael Rollins over her petition that Judge Richard Sinnott cannot force her to prosecute a 'Straight Pride' parade counter-protester. WGBH Morning Edition Host Joe Mathieu spoke with Northeastern University law professor and WGBH News legal analyst Daniel Medwed about what the ruling means. The transcript below has been edited for clarity.

Joe Mathieu: I know you didn't expect [the decision] to come quite as soon as it did, but what was at stake in this filing? What was the exact impact of the ruling?

Daniel Medwed: Well, Rachael Rollins had filed an emergency petition with a single justice of the SJC, pursuant to a very peculiar procedure. If you're aggrieved by a decision of a lower court, you feel as though there's been an abuse of power and there's no other remedy available, you can seek review from our highest court. Here, Rachael Rollins was seeking review of one decision by Judge Sinnott. He had declined to enter what's called a nolle prosequi [petition] — or nol pros for short — filed by the prosecution. Prosecutors may unilaterally file one of these petitions when they don't want to proceed in a case. They typically reserve the right to reconsider down the road. Sinnott had rejected this nol pros petition for a protester named Roderick Webber, and Rollins was claiming this violated the separation of powers and the absolute authority of prosecutors to file these petitions. Justice Gaziano, as you pointed out ... very quickly, in a matter of days, sided with Rollins, cited precedent from 1806, talking about the absolute power of prosecutors to file these petitions. The upshot is that Webber's case is gone. His record is expunged.

Mathieu: And, to be clear, this is a single case we're talking about, but it could set precedent for the others?

Medwed: That's right.

Mathieu: Now, Daniel, there is clearly some confusion here because we're hearing from different sides on this. Who in fact has the ultimate authority, then, to dismiss a criminal case? Is it in fact the prosecutor or the judge?

Read More: DA Rollins: Judge's Behavior 'Unhinged' In 'Straight Pride' Parade Dispute, Represents Larger Issue

Medwed: It's surprisingly complicated. Here's how it works. Prosecutors, of course, represent the executive branch. They execute the law [and] enforce the law, and therefore they have the right to bring criminal cases and to choose not to prosecute. If they want to get rid of a case, they typically have two options. On the one hand, they can file one of these nol pros petitions as occurred in the Webber case. That power resides with the D.A. On the other hand, they could ask the judge to formally dismiss the case entirely. And the judge, as the overseer of the court system, has the power to enter those dismissal orders. It's very unusual for a judge to turn down either a nol pros petition or a formal request for a dismissal order from the district attorney.

Mathieu: So tell us specifically what the judge did, and then I'll ask you about that decision.

Medwed: Sure. So what happened here is he not only turned down that one nol pros petition for Roderick Webber, but he also rejected eight requests for dismissals for 'straight pride' [counter-]protesters. I find this utterly baffling in part because it's not as if Rollins' office wanted to drop every case related to the straight pride parade. In fact, of the 36 cases pending last week, she indicated that she wanted to proceed in eight of them — the eight cases involving allegations of violence. This is entirely consistent with her philosophy: clamp down [and] prosecute violent crimes, but exhibit mercy, humanity [and] discretion for nonviolent crimes.

Mathieu: Is this decision by the judge really about that? Why did he make this decision? Is it a political statement?

Medwed: That's the million dollar question here. I'm somewhat reluctant to probe into his internal motivation, but I will say this: a charitable interpretation of Sinnott's behavior suggests that he was concerned about compliance with our victim's rights law. Under that law, you have to notify victims before a case is dropped. He claimed that the organizers of the "Straight Pride" parade were victimized by these resisting arrests and disorderly conduct cases. In my view, that's a specious argument. That's a stretch to say that the organizers were aggrieved or harmed by these incidents. It's patently absurd. So I think a less charitable interpretation and a more accurate interpretation of his behavior is that it's a culmination, a boiling over, of this long-simmering dispute between entrenched members of law enforcement, judges and Rollins' progressive agenda.