Massachusetts has not been as quick to act as states such as North Carolina and Iowa, which have implemented new laws since June, when the US Supreme Court banned mandatory life without parole for ­juveniles convicted of murder. While change is expected in Massachusetts, either through the courts or legislation, no clear answers have emerged on how to handle new cases and review past convictions involving killers under 18.

Governor Deval Patrick’s point person on the issue wants life without parole banned entire­ly for juveniles, whether mandatory or not. Middlesex County District Attorney ­Gerard T. Leone Jr. wants teenage killers to serve a minimum of 35 years before becoming eligible for parole, while the Massachusetts District Attorneys Association has reached no consensus on a solution.

Meanwhile, the state’s public defenders office has mobilized and trained dozens of ­defense lawyers to work with as many as 80 inmates and ­accused teenage killers in Massa­chusetts who could be ­affected by the ruling.

The 5-4 Supreme Court decision in Miller v. Alabama banned the mandatory sentence, imposed in 29 states, as “cruel and unusual punishment,” but still gives judges discretion to impose life without parole for teenage killers.

Last week, a Middlesex ­Superior Court judge wrote the first decision in the state discussing the consequences of the high court ruling, arguing that the only option available to judges now is to sentence teenage killers to life in prison with the possibility of parole. Legislation would be required, wrote Judge Kathe M. Tuttman, only if the state determines it wants the option to sentence juveniles to life without parole, a process that she said would require legislative guidelines.

The ruling tore open a door victim’s families thought was locked forever. Across the country, more than 2,100 individuals are serving mandatory sentences of life without parole for murders committed while they were under 18, said Marsha Levick, deputy director and chief counsel of Philadelphia’s Juvenile Law Center.

Jennifer Bishop Jenkins of Illinois, head of the National Organization of Victims of ­Juvenile Lifers, said states should not change law in ­response to the decision without talking to victim’s families.

“Of course, the uncertainty of these months after [the Miller case] is painful for these families,” said Bishop Jenkins, whose sister, brother-in-law, and unborn child were killed by a teenager now serving three life sentences. “Swift [action on the issue] can be good for victims, if it is thorough and properly done, but the state of Massa­chusetts cannot act until they talk to ­every family of a Massachusetts victim. Most of these families have had to wait for justice in any case.”

The high court gave states no specific guidance on how to apply the decision, nor indicated whether it should be applied retroactively to those already sentenced.

But the decision mandated that at least going forward, if prosecutors want juveniles to serve life without parole, the defendants are entitled to individualized sentencing hearings that consider factors such as their home life, intellect, and emotional capacity at the time of the slaying.

According to the Massachusetts Committee for Public Counsel Services, at least 80 people could be affected by the high court decision: the 62 ­inmates imprisoned for murders committed as juveniles and another 18 who have been convicted since June but not yet sentenced, whose cases were on appeal at the time of the high court ruling, and teenagers ­arrested since June on murder charges.

A bill to allow juveniles serving life without parole a chance at release after serving 15 years, which was proposed long ­before the high court decision, died in the last legislative session. and no new proposals have been submitted, said Gail Garinger, Massachusetts child advocate and Patrick’s top liaison on the issue.

In Massachusetts, unlike in other states, no teenage killers have filed motions for resentencing following the decision, but legal developments are ­unfolding in other ways.