Last week, a Suffolk County judge rejected an effort by the Massachusetts state police union to block Governor Baker’s COVID-19 vaccine mandate from taking effect in October. Daniel Medwed, GBH News legal analyst and Northeastern University law professor, joined Aaron Schachter on Morning Edition to discuss the lawsuit. This transcript has been edited for clarity and length.

Aaron Schachter: Now Daniel, we’ve chatted about vaccine mandates before but let’s start with a brief recap: Is there much of a question about whether state-sanctioned COVID-19 vaccine mandates are legal?

Daniel Medwed: Not really, especially now that the FDA has fully approved the current vaccines, as long as the mandate is reasonable and makes accommodations for religious and medical exemptions. First, consider the public policy — states have the right to regulate during public health crises to protect their residents, for instance, by imposing mask requirements or travel quarantines, and vaccine mandates are just an outgrowth of that principle.

Second, there’s important U.S. Supreme Court precedent on that point, a1905 case that arose in Cambridge during the smallpox epidemic, where a Swedish pastor refused to take the vaccine for health reasons and the city levied a fine. He challenged it all the way through the courts. In a 7-2 decision, the Supreme Court ruled in favor of Cambridge, holding that “every well-ordered society” is obligated to keep its citizens safe and that sometimes — “under the pressure of great dangers” — citizens may be subject to “reasonable regulations.”

Schachter: So, what was the union’s legal argument in this suit? Was it claiming Baker’s vaccine mandate was unreasonable and shouldn’t apply to state police?

Medwed: Not directly. Technically, the legal challenge was more of an indirect attack on the mandate, revolving around labor law and what the union claims are its rights under the public employee collective bargaining law. Specifically, the union sought an injunction from the court to enjoin or stop implementation of the Governor’s Executive Order that requires all Massachusetts executive branch employees to be fully vaccinated by October 17 to allow time to negotiate over the various terms of the mandate as part of the collective bargaining process.

Schachter: So, Daniel, you just mentioned that the union wanted to negotiate over the terms of mandate. What exactly did it want?

Medwed: The lawsuit gave insight into what the union might prefer. For one thing, the union drafted its own policy that would make October 17 the starting date, rather than the completion date, of the vaccination process. It also proposed weekly testing and mask-wearing as an alternative to vaccination. For another, and this is huge, it wanted assurance that any COVID-19 illness incurred by a union member would be treated as a line-of-duty injury and therefore entitled the person to benefits.

Schachter: Now the Suffolk County judge, Jackie Cowen, refused to grant the injunction. What was her legal reasoning?

Medwed: Well, under Massachusetts law, for an injunction like this to succeed, the plaintiff — the union — must show a likelihood of winning the lawsuit eventually, that refusing to issue the injunction would cause irreparable harm and that, in turn, granting it would advance the public interest. Judge Cowen focused on those last two requirements, finding that the union had not identified any irreparable harm to its members and, most poignantly, framed its discussion of the public interest too narrowly.

That is, Cowen emphasized that the union’s arguments emphasized the interests of its members “to the exclusion of everyone else,” that the public interest is, “unquestionably, best-served by stopping the spread of the virus” and that vaccination is “the most effective means of doing that.”

Schachter: Is the upshot that unvaccinated state police will get a jab before mid-October?

Medwed: Some of the estimated 20% of state police who remain unvaccinated might get a jab; others might resist and face progressive discipline under the terms of the Executive Order, including possible termination, and others might quit to join municipal police departments that allow testing and masking as an alternative.