The Massachusetts Supreme Judicial Court holds oral arguments in appellate cases during the first week of each month from September through May. This month, the SJC ruled against the appeal of a man convicted of murder, who says he didn't receive a fair trial. His defense argued that a judge's decision to block lawyers from questioning witnesses about their immigration statuses limited their ability to advocate for their client. In another case this month, which garnered national attention, a man is appealing his conviction of drug distribution and involuntary manslaughter. Morning Edition Host Joe Mathieu spoke with WGBH News legal analyst and Northeastern law professor Daniel Medwed about recent developments at the SJC. The transcript below has been edited for clarity.

Joe Mathieu: Before we turn to this week's oral arguments, there was one notable decision by the SJC just last week.

Daniel Medwed: That's right. It was a very important decision in the field of “crimmigration,” which is the nexus between criminal law and immigration. What happened was that a man named Fredys Chicas was charged with murder related to the beating death of another man in Chelsea back in 2005. Before trial the government disclosed to the defense that about six or seven of the eyewitnesses happened to be illegal aliens — they were undocumented immigrants. The defense, in turn, wanted to cross-examine those witnesses at trial about their immigration status, based on the theory that it somehow bore upon their credibility, their capacity to tell the truth. The trial judge refused to allow that line of questioning. Chicas was convicted and appealed it all the way up to the SJC, claiming he was deprived of his right to a fair trial.

Mathieu: What was the defense claim here? How was he allegedly denied a fair trial?

Medwed: The basic argument went like this: under the Constitution, the Sixth Amendment to the Constitution, criminal defendants have a right to confront the witnesses against them, their accusers, and cross-examination is the typical way of extinguishing that right. Cross-examination, in turn, typically includes asking questions that could expose an incentive or bias on the part of a prosecution witness. According to the defense, here the witnesses' immigration status suggested they had an incentive to please the prosecution. Otherwise there was the fear of deportation, and that the jury should have been aware of this. That's basically the defense claim.

Mathieu: Did the SJC buy it?

Medwed: Well, the defense sold it, but the SJC wasn't buying it. In a unanimous decision, the SJC affirmed Chicas' conviction, and in the process made a couple of compelling points. First, the SJC disputed the defense's characterization of the incentives of undocumented immigrants. On the contrary, according to the SJC, this segment of the population is among the least likely to cooperate with the government — that they'd rather remain outside the government's purview, and therefore questions about immigration status have little-to-no bearing on their capacity to tell the truth on the stand. Second, the SJC reaffirmed a longstanding appellate principle, that decisions about the proper scope of cross-examination at trial properly reside within the discretion of the trial judge, and the trial judge did not abuse her discretion here.

Mathieu: So it's another sign, essentially, the state is protecting the interests of undocumented residents?

Medwed: That's right.

Mathieu: We're talking with legal analyst Daniel Medwed about recent developments at the SJC, the Supreme Judicial Court, which we'll be watching out for this week.

Medwed: Well the big case was argued just yesterday, on Monday. Commonwealth vs. Carillo. This is a case involving a UMass Amherst student who purchased some heroin and gave some of it to his friend who proceeded to die of an overdose. The supplier of the drugs, Mr. Carillo, was then charged with manslaughter — homicide related to the overdose death of his friend. A very controversial type of prosecution. On the one hand, many observers — and I'm in this camp — think it's an overreach, a real stretch. In part because the user made the decision himself to ingest the drugs, breaking the chain of causation between the seller and the end result.

But on the other hand, it's understandable that prosecutors are at their wits end about how to grapple with the opioid crisis, and it makes sense to some extent that they would resort to aggressive tactics to try to deter sellers from basically peddling unsafe products. What does seem clear, though, is these prosecutions are on the rise nationally. A team of researchers at Northeastern, including my colleague Leo Beletsky, have detected 35 similar prosecutions in Massachusetts, and, get this, more than 600 in the state of Pennsylvania alone.