The pronouncement followed US Attorney General Jeff Sessions’ decision last week to grant regional federal prosecutors broader discretion to enforce the longstanding national prohibition on cannabis, which the Obama administration had limited in states that have approved the drug for recreational or medical use.

“I cannot . . . provide assurances that certain categories of participants in the state-level marijuana trade will be immune from federal prosecution,” said US Attorney for Massachusetts Andrew E. Lelling.

The state’s top federal prosecutor on Monday refused to rule out a crackdown on the voter-authorized marijuana industry, prompting howls from advocates and politicians and moving Massachusetts to the forefront of the battle between the Trump administration and the dozens of states where cannabis is legal.


Lelling’s statement — which struck a more aggressive tone than those from other federal prosecutors and comes as the state prepares for the debut of recreational pot sales — was released hours after the sponsors of 2016’s successful marijuana legalization initiative called on him to clarify his intentions under the new policy.

“This is a straightforward rule of law issue,” Lelling responded. “Congress has unambiguously made it a federal crime to cultivate, distribute, and/or possess marijuana. As a law enforcement officer in the executive branch, it is my sworn responsibility to enforce that law.”

However, Lelling also said he would assess on a case-by-case basis whether it was worth using “limited federal resources” to clamp down on marijuana operations.

Only Congress can end the federal prohibition on pot, the prosecutor added.

But state Attorney General Maura Healey said she did not think Lelling’s statement offered sufficient guidance.

“The people of Massachusetts voted to legalize the responsible sale and use of marijuana,” said a Healey spokeswoman. “Our office is com-mitted to helping implement legalization effectively and as safely as possible. We encourage the US attorney to further clarify his enforcement priorities to provide guidance to Massachusetts municipalities, residents, and businesses.”


Lelling’s stance also miffed a range of Massachusetts leaders who have been grappling with regulating the state’s nascent marijuana market.

Geoff Beckwith, executive director of the Massachusetts Municipal Association, said the newly hostile signals from the federal government threaten to confuse ongoing local efforts to prepare for recreational marijuana.

“This is a knuckleball late in the process,” Beckwith said. “It’s a disruptive intrusion by the federal government into the activities of state and local governments, who have been working on this structure and implementing the will of the voters.”

The state’s top two legislative leaders, House Speaker Robert A. DeLeo and acting Senate President Harriette L. Chandler, said at the State House Monday the recent federal directives have created great uncertainty.

“If you’re a person who is looking to come into Massachusetts and to open up a cannabis business,” DeLeo told reporters, “I’m not sure what type of message that sends or what type of security that gives you — or lack of security, I should say.”

After meeting with the legislative leaders, Governor Charlie Baker left through a back door, bypassing about a dozen members of the news media, some camped out to ask him questions about Lelling’s stance. (Officials said he was running behind schedule.)

In a statement, a Baker spokeswoman said the governor will continue to support the mission of the state agency overseeing legal pot and adequately fund its work.


Sessions last week rescinded Obama-era Department of Justice policies that had sharply limited prosecution of dispensaries, banks, and other participants in state-regulated marijuana markets. As a result, each regional US attorney now has more flexibility to enforce — or not — the federal prohibition on production and sale of the drug in states such as Massachusetts where it is legal.

While federal prosecutors in some other parts of the country suggested state-licensed marijuana growers and retailers wouldn’t be the focus of enforcement efforts, Lelling, a Trump appointee who took office on Dec. 21, has declined to make such a pledge.

The prosecutor left open the possibility he would spare state-regulated companies to focus federal law enforcement resources on illicit growers and dealers.

But last week he called marijuana a “dangerous drug” and said his office would go after “bulk cultivation” operations. And in an e-mail to chiefs of local police departments across Massachusetts, Lelling asserted that cannabis had a “direct and negative impact on the communities we serve” and promised to “vigorously enforce” federal law.

“He sure is rattling his saber loudly — more, I think, than any other US attorney,” said Steven S. Epstein, a Georgetown lawyer and longtime legalization activist. “But I don’t think he’s going to be using it.”

Prosecuting people who are operating legally under state law would be “a gamble” for Lelling, Epstein said, since a jury might be reluctant to convict the owner of a cannabis business regulated and licensed by the state.


Still, experts said Lelling could constrain the industry’s growth without ever launching a raid.

The mere prospect of renewed federal enforcement against marijuana operations will likely discourage investment in the space, and it might prompt banks to drop dispensaries as clients. The federal threats, they said, will also reduce the incentive for underground operators to join the state-legitimized market, thereby sustaining the illicit market and further undermining licensed companies.

“Absent the regulated market, the state will have widespread demand fed by an unregulated market with less safe products sold in a far more dangerous environment,” said Adam Fine, an attorney who represents cannabis companies in Massachusetts.

But others in the marijuana industry downplayed Lelling’s comments, saying cannabis has always been illegal at the federal level and that investors in the space are comfortable with the risk. They also argued that the new federal policy could backfire on Sessions by prompting Congress to consider ending the prohibition on marijuana.

“The cannabis industry is too big to go back into the shadows now,” said Beth Waterfall, a marijuana activist and founder of a nonprofit cannabis networking group. “We’re already seeing opposition from all sides of the political spectrum, which is only galvanizing support for change to marijuana’s federal legal status.”

Earlier on Monday, the group behind the state’s legalization ballot initiative pressed Lelling for a commitment that he wouldn’t target state-licensed marijuana operations and their banks, saying voters in Massachusetts “deserve clear, unambiguous answers.”

Massachusetts voters approved Question 4, which legalized marijuana, by a vote of 54 percent to 46 percent in 2016. Recreational pot sales are on track to begin in July under the supervision of the Cannabis Control Commission.


A congressional budget rider bars the Department of Justice from spending money on most prosecutions of state-licensed medical marijuana operations, meaning the state’s currently operating dispensaries should be safe for now.

However, that amendment is due to expire later this month along with the current federal budget. Sessions previously called on Congress to drop the language.

The cannabis commission is scheduled to meet Tuesday morning. Asked for comment, a spokeswoman for the agency pointed to a statement it issued last week that promised to forge ahead with finalizing regulations.

Dan Adams can be contacted at daniel.adams@globe.com. Follow him on Twitter @Dan_Adams86. Joshua Miller can be contacted atjoshua.miller@globe.com. Follow him on Twitter @jm_bos.