A decision by Attorney General Jeff Sessions to rescind an Obama-era policy that discouraged U.S. attorneys from enforcing federal marijuana laws at odds with state laws met with sharp criticism from associations in the cannabis industry this week.

The change, announced in a memo [PDF] on Thursday, came a mere four days after the state of California, the first to allow marijuana to be used for medicinal purposes, legalized the drug’s recreational use. And groups focused on the state’s fledgling industry were quick to respond to the attorney general’s move.

Hezekiah Allen, the California Growers Association’s executive director, told The New York Times that the support of a state government could help the industry stay strong even if the federal government pushes for stricter enforcement.

“Folks that have been at this for a few generations remember that this is a cycle,” Allen told the newspaper. “Federal enforcement ebbs and flows, and it has for decades. This is another enforcement cycle, but this time we have a state government that is working with us. And, frankly, enforcement wasn’t all that effective in the past.”

Other state-level groups, including the Arkansas Medical Marijuana Association and Arizona’s Marijuana Industry Trade Association, expressed a similar mixture of concern and skepticism over the policy change.

At the national level, Aaron Smith, executive director of the National Cannabis Industry Association, said that while the change is “disturbing, especially in light of the fact that 73 percent of voters oppose federal interference with state cannabis laws,” it doesn’t necessarily mean anything will change.

“This has been, and still will be, a matter of prosecutorial discretion,” Smith said in a news release. “We therefore hope that Department of Justice officials, including U.S. attorneys, will continue to uphold President Trump’s campaign promise to not interfere with state cannabis programs, which have been overwhelmingly successful in undercutting the criminal market.”

It’s possible that the Sessions memo will have a limited effect in the short term. The Times report noted that the Justice Department’s Drug Enforcement Administration has limited resources and that they are currently focused on the opioid crisis.

Meanwhile, an existing law called the Rohrabacher-Farr amendment prevents federal interference with state medical marijuana programs. However, the measure, which was passed as part of a spending bill in 2014, must be renewed every year and may not make it into a future budget bill, as it is opposed by Sessions.

Some groups welcomed Sessions’ move. Smart Approaches to Marijuana, a group founded in 2013 that publicly opposes legalization, hailed the policy change.

“This is a good day for public health. The days of safe harbor for multimillion-dollar pot investments are over,” SAM CEO Kevin Sabet said in a news release. “DOJ’s move will slow down the rise of Big Marijuana and stop the massive infusion of money going to fund pot candies, cookies, ice creams, and other kid-friendly pot edibles. Investor, banker, funder beware.”

Attorney General Jeff Sessions. (Gage Skidmore/Flickr)