Harborside CEO Steve DeAngelo talks with a reporter at the cannabis dispensary Thursday, Jan. 4, 2018, in Oakland, Calif. Attorney General Jeff Sessions has rescinded an Obama-era policy that paved the way for legalized marijuana to flourish in states across the country, creating new confusion about enforcement and use just three days after a new legalization law went into effect in California. (AP Photo/Terry Chea)
Harborside CEO Steve DeAngelo talks with a reporter at the cannabis dispensary Thursday, Jan. 4, 2018, in Oakland, Calif. Attorney General Jeff Sessions has rescinded an Obama-era policy that paved the way for legalized marijuana to flourish in states across the country, creating new confusion about enforcement and use just three days after a new legalization law went into effect in California. (AP Photo/Terry Chea) Credit: Terry Chea

Washington — Attorney General Jeff Sessions on Thursday made it easier for U.S. prosecutors to enforce federal marijuana laws in states that had legalized the substance — drawing swift criticism from jurisdictions that have approved pot use and stirring confusion among entrepreneurs in the burgeoning billion-dollar industry.

Whether Sessions’ Justice Department actually busts dispensaries or others involved in state-approved pot production remains to be seen, but his decision to undo previous guidance and possibly put a federal crackdown on the table riled business people, legislators and civil liberties advocates across the country.

Though marijuana already was illegal under federal law, the Justice Department during the Obama administration had issued guidance — which Sessions revoked — discouraging enforcement of the law in states where it was legal.

Eight states and the District of Columbia have laws allowing for recreational marijuana consumption, according to NORML, a group that advocates legalization and tracks pot-related legislation. Many more permit the use of medical marijuana.

Those opposing federal pot laws said they felt Sessions was trying to stop the country’s momentum toward full legalization of marijuana — which just days earlier had become legal to some fanfare in California. They warned that Sessions wants to impose his view that the country should return to the war on drugs. Sen. Cory Gardner, R-Colo., a member of Sessions’ political party, even threatened to hold up the confirmation of nominees for key Justice Department leadership posts in response.

Sessions countered that he was merely enforcing federal law, which prohibits marijuana use, and giving discretion to U.S. attorneys.

“It is the mission of the Department of Justice to enforce the laws of the United States, and the previous issuance of guidance undermines the rule of law and the ability of our local, state, tribal and federal law enforcement partners to carry out this mission,” the attorney general said in a statement. “Therefore, today’s memo on federal marijuana enforcement simply directs all U.S. attorneys to use previously established prosecutorial principles that provide them all the necessary tools to disrupt criminal organizations, tackle the growing drug crisis, and thwart violent crime across our country.”

Sessions announced his decision in a memo sent to U.S. attorneys. He said prosecutors should disregard the old guidance and instead use their discretion — taking into consideration the department’s limited resources, the seriousness of the crime, and the deterrent effect that they could impose — in weighing whether charges were appropriate.

Soon after the decision became public, Gardner wrote on Twitter the move “directly contradicts what Attorney General Sessions told me prior to his confirmation,” and he was “prepared to take all steps necessary, including holding DOJ nominees, until the attorney general lives up to the commitment he made to me prior to his confirmation.”

The Department of Justice still lacks leaders in several key spots, including heads of the national security, criminal and civil rights divisions. In an interview, Gardner said that while he personally opposed marijuana legalization, his state voted otherwise.

Even President Donald Trump had said in 2016 that he would not use federal authority to shut down sales of recreational marijuana and instead believed the matter should be left “up to the states.”

White House press secretary Sarah Huckabee Sanders said on Thursday, though, that Trump “strongly believes that we should enforce federal law” and the Justice Department’s move “simply gives prosecutors the tools to take on large-scale distributors.”