A letter from Attorney General Jeff Sessions to leaders of Congress is the most recent in a long list of signals that the Trump administration is trying to crack down on marijuana sales.

Sessions sent a letter to leaders of Congress in May asking them to allow the Justice Department to prosecute businesses and individuals in states where medical marijuana is legal.

In the letter, Sessions asked the heads of both parties in the Senate and in the House of Representatives to undo medical-marijuana protections that prevent the Justice Department from using federal funds to enforce federal prohibition laws in states where medical-marijuana laws have been implemented.

The Hinchey-Rohrabacher Amendment, which enables such protections, is tied to the federal appropriations bill.

“I believe it would be unwise for Congress to restrict the discretion of the department to fund particular prosecutions, particularly in the midst of an historic drug epidemic and potentially long-term uptick in violent crime,” Sessions wrote.

The industry is in denial, said Rafael Lemaitre, former associate director for public affairs for the Drug Policy Office under President Barack Obama.

“I don’t know how much more clear [the administration] needs to be on this,” Lemaitre said. “No one knows what’s going to happen, but this should scare anyone involved in the marijuana industry.”

People entering the marijuana industry have always needed to be risk averse, even in the Obama era, Lemaitre said. But anyone showing interest under the current administration has to be a little crazy, he quipped.

Lemaitre said it’s not likely the industry will see the federal government crack down by way of raids on dispensaries — they don’t have the resources — but said the industry could see backlash from the federal government.

And he didn’t seem to have much faith in an industry “resting its entire existence on a three-page Obama-era memo,” Lemaitre said, referring to the Cole Memo, which prevents the federal government from interfering with states that legalize recreational and/or medical marijuana as long as they abide by a series of guidelines.

Marijuana legalization supporters aren’t phased by Attorney General Sessions’ letter and the Marijuana Policy Project still has hope Congress will defend the industry’s protections.

“Law enforcement agencies always want every resource available and with as few restrictions as possible,” said Mason Tvert, communications director for the Marijuana Policy Project. “Most members of Congress agree the Justice Department should not be using federal tax dollars to meddle in state medical marijuana programs, and we hope they will rebuke the attorney general’s request.”