BOSTON — One big question marijuana entrepreneurs will face in states like Massachusetts is whether federal agents will crack down on the state-sanctioned business, which is still illegal under federal law.

At a gathering of policymakers from around the country on Monday, a lawmaker from Washington state, a Vanderbilt University law professor and a Brookings Institute fellow all suggested pot proprietors can breathe easy.

The three experts, who spoke on a panel held by the National Conference of State Legislatures in Boston, each said tight funding and other pressures should keep federal law enforcement at bay.

“Trying to roll it back and trying to go back to the old War on Drugs – the terribly failed system – they will do it at their own peril,” Rep. Roger Goodman, a Democrat who lives outside Seattle, told the gathering at the Boston Convention and Exhibition Center.

Vanderbilt Law School professor Robert Mikos told the News Service a federal appeals court ruled that current appropriations law bars the Department of Justice (D.O.J.) from prosecuting cases against medical marijuana dispensaries that are in compliance with local laws.

Last November, Massachusetts voters legalized adult possession and cultivation of marijuana, and this summer state lawmakers overhauled the ballot law’s system for regulating retail sale of the intoxicant. Medical marijuana dispensaries that were legalized in 2012 are already up and running in the Bay State, and top lawmakers anticipate the first legal pot shop will open next summer.

Under a 1970 statute, marijuana is considered among the most dangerous drugs under federal law, and federal officials patrolling federal land, military installations and offshore areas intend to continue enforcing the prohibition. The bigger question for Massachusetts and other states that have legalized retail sale is whether federal agents will come after marijuana businesses that are in compliance with state regulations.

Attorney General Jeff Sessions has asked lawmakers to give the D.O.J. authorization to prosecute medical marijuana dispensaries, according to the Washington Post, which reported the Obama administration also sought to “undermine” the existing ban on prosecution. According to the Associated Press, a task force Sessions assembled this year to look at marijuana and other criminal policies came up with a report that “largely reiterates the current Justice Department policy on marijuana.”

At a speech in Dallas in July, Sessions suggested society has been too lax in its approach to drug abuse, according to his prepared remarks.

“Now, some people today say that the solution to the problem of drug abuse is to be more accepting of the problem of drug abuse. They say marijuana use can prevent addiction. They say the answer is only treatment. They say don’t talk about enforcement. To me, that just doesn’t make any sense,” Sessions said. “In fact, I would argue that one reason that we are in such a crisis right now is that we have subscribed to this mistaken idea that drug abuse is no big deal.”

Mikos advised state lawmakers that they could establish an indemnification fund to provide legal defenses if federal prosecutors decide to bring cases against those engaged in the marijuana industry. But Mikos doesn’t think there is much of a risk to the regulated marijuana industry.

“D.O.J. for one thing doesn’t have the resources that would be necessary to make a really effective crackdown,” Mikos told the News Service. He said the U.S. attorneys who will be appointed by President Donald Trump to handle local prosecutions are “much more in tune with local politics, and they’re much more leery about shooting themselves in the foot longterm by bringing a federal case.”

John Hudak, of the Brookings Institute, agreed that resources are scarce at the Justice Department, and said cracking down on marijuana business would carry reputational risks for the attorney general.

“The worst embarrassment for Jeff Sessions would be to try to restart the War on Drugs and fail miserably in enforcing it,” Hudak said.

A 2013 D.O.J. guidance memo suggested robust state regulation of legal marijuana businesses could accomplish federal priorities of preventing the drug from falling into the hands of minors, cutting off funding to drug gangs and reducing gun violence – without additional federal enforcement.

Goodman, who grew up in Providence, R.I., and represents clients in the marijuana business as a lawyer, said federal officials have indicated prosecuting marijuana dispensaries is not a priority.

“We’ve heard in private conversations that they have other priorities and they have limited resources, and they think that the current federal enforcement guidelines are very helpful. And so we’re encouraged that despite the public sabre rattling, that the federal government is going to be finding other enforcement priorities,” Goodman said. Regarding his roles as state lawmaker and lawyer who represents clients in the marijuana business, Goodman said, “I take great pains to prevent even the perception of conflict of interest … I’ve voted for bills that were contrary to the interests of a number of my clients.”