Justices of the state’s highest court dug in Monday on arguments of local control, the power of voters to make decisions for a municipality and the differences between “guidelines” and “regulations” as the Supreme Judicial Court took up Attorney General Andrea Campbell’s push to force Milton to comply with a 2021 zoning law.

The SJC took the case on because of the new and important public policy issues it deals with, namely what legal obligations 177 affected towns have and the state’s enforcement powers under the so-called MBTA Communities Act, which mandates multi-family zoning by right in transit-adjacent communities.

Campbell sued the town of Milton and its building commissioner in February, shortly after voters approved a referendum put forward by residents worried about the potential for excess development under the zoning reform plan that Milton Town Meeting initially approved last year. The state is seeking a court order that would force the town into compliance.

But the town, where voters were heard at the ballot box earlier this year, contends that the only punishment for noncompliance is the loss eligibility for certain grant programs that are specifically spelled out in the statute. Milton has already lost some grant funding, and the town government argues that the attorney general should not have the power to take additional enforcement action against it.

Over the course of nearly an hour, six of the seven SJC justices (Justice Bessie Dewar, the former state solicitor, did not participate) heard from both sides and were active in their questioning. The primary line of argument related to Campbell’s powers to enforce the law beyond what is specifically called for in the law.

“Towns can’t vote not to comply with state laws, right? So if you have the authority in the AG’s office … then the question is, are the remedies exclusive? That’s really the only issue we have,” Justice Scott Kafker said Monday.

Assistant Attorney General Eric Haskell argued that the remedies detailed in the law are not exclusive, and agreed with Kafker’s contentions that the loss of grant funding is largely a “paper tiger” and that “without your ability as the AG to enforce this, there’s no real remedy here.” Haskell said that the last time Milton got any money from one of the specified grant programs was $1 million it received through the MassWorks program in 2012.

“Our view is that the Legislature included that in there so that municipalities would know there is going to be a concrete consequence of not complying, and it’s going to be automatic, and it’s going to be swift, and it’s going to be certain,” he argued Monday. “But it does not in any way take the place of the power of the attorney general to enforce this mandatory state law.”

The high court also spent time unpacking Milton’s argument that it is not in violation of the MBTA Communities Act because the guidelines the Legislature required the Executive Office of Housing and Liveable Communities to produce were not properly promulgated. The law itself mandated EOHLC to “promulgate guidelines to determine if an MBTA community is in compliance with this section,” and Milton argues that the guidelines are really regulations that should have been promulgated following the specific process laid out in Chapter 30A.

Justices Frank Gaziano and Gabrielle Wolohojian both raised with Haskell the possibility that the court could decide that the guidelines as issued by EOHLC are unenforceable because they were not put into effect using the proper process. Wolohojian pressed Haskell on how the state’s argument that Milton violated the law when it missed its deadline to comply would be affected if the court were to effectively dismiss the guidelines that created the deadline.

“I think if the decision from this court comes out in a way that HLC needs to repromulgate the guidelines, it would be HLC’s choice in that situation what to do by way of deadlines. I think it’s safe to assume they couldn’t specify a deadline in the past,” he said. Haskell argued, though, that the court would still need to settle the first question of the AG’s authority to force the town into compliance.

Wolohojian didn’t entirely agree. She said that the enforcement question “wouldn’t apply to Milton, though” if the guidelines were deemed unenforceable.

“If I understand correctly, the point at which Milton, in your view, violated the statute, was when it didn’t enact a zoning plan by a certain date. But if the certain date only comes from the guidelines and the guidelines need to be done over then, then what is there to enforce against Milton?” she asked.

There are 177 communities that either have or will have to rezone to encourage multi-family housing because they either host or are adjacent to MBTA service. State lawmakers wove the mandate into a 2021 economic development package at the last minute with little discussion, but the provisions has become a major piece of the state’s strategy to encourage badly needed housing production.

Most municipalities in the eastern part of the state are closely watching Milton’s case before the SJC. The Boston suburb is so far the only town to have missed its final deadline to comply. But dozens of other communities face an end-of-2024 deadline to come into compliance and some have been considering referendums to similarly ignore the law.

The justices of the SJC did not offer a timeline for their decision Monday. The court says that most cases are generally decided within 130 days of oral arguments, which would mean by mid-February for cases heard Monday.