On Thursday, Jeff Sessions rescinded the Cole Memorandum, ending an understanding between federal authorities and states with legal marijuana. The move raised fears of an impending crackdown and further cements Sessions’s reputation as an anti-pot crusader.

While marijuana remains illegal at the federal level, the Cole memo, issued by Deputy Attorney General James Cole in 2013 under Former President Barack Obama, says the feds shouldn’t prioritize going after people in “tightly regulated market[s] in which revenues are tracked and accounted for.” The memo also said prosecutors shouldn’t consider “the size or commercial nature of a marijuana operation alone” when deciding to press charges.

In a one-page memo of his own, Sessions framed his new policy as a return to “well-established principles.” Noting the federal government gives “significant penalties” for pot crimes, Sessions said the Cole memo was “rescinded, effective immediately.”

What happens next is unclear. When the Cole Memo was written, two states — Colorado and Washington — had fully legal pot. Now, eight states allow for recreational marijuana. And almost every state has some kind of medical marijuana program, in direct violation of federal law. The only exceptions are Kansas, Idaho and Nebraska.

Sessions’s decision prompted a fierce backlash from the cannabis community and from people in legal states. In a statement, Erik Altieri, executive director of the National Organization for the Reform of Marijuana Laws (NORML), described the change as “a disaster.” Colorado Senator Cory Garner, a Republican, tweeted that the move had “trampled on the will of the voters.” And in a formal letter to Sessions, the governors of Alaska, Colorado, Oregon and Washington warned that “overhauling the Cole Memo is sure to produce unintended and harmful consequences.”

Sessions, who holds a variety of antiquated views on cannabis and who has said “good people don’t smoke marijuana,” has long pushed for a return to zero-tolerance drug enforcement. Last May, he undid another Obama-era directive, intended to prevent overuse of mandatory minimum sentences, and said prosecutors should instead charge defendants with “the most serious, readily provable offense.”

Still, panicking now is probably premature, for a few reasons. If Sessions wanted another War on Drugs, he’d need the help of federal prosecutors. So far, though, U.S. attorneys in legal states have shown little interest in joining his crusade, and state attorneys general have vowed to fight him. In a statement Thursday, Ellen Rosenblum, attorney general for Oregon, said she “will do everything within my legal authority” to protect marijuana businesses.

For another thing, most Americans disagree with Sessions. In a Gallup poll last October, 64 percent of Americans said pot should be legal. Last year, for the first time ever, a majority of Republicans said the same.

These polls suggest a decent number of President Donald Trump’s young supporters are in favor of legal pot (and may even smoke themselves). And while marijuana is popular, Trump, with his current 38 percent approval rating, is not. The idea of the Trump Administration, already embroiled in countless other controversies, going to war with a popular industry seems ridiculous, even by current standards. Especially since Trump, who said repeatedly while campaigning that he wouldn’t crack down on legal pot, doesn’t seem to have any particularly strong views on the drug.

Sessions is right that about the fed’s strict stance on cannabis. The official position, last updated in 1971, is that pot has “no currently accepted medical use” and “a high potential for abuse.” But one consequence of this extremely outdated policy is that basically no one outside the DEA takes it seriously. When Texas lawmakers set up a marijuana program in 2015, they flouted federal guidelines by telling physicians to “prescribe,” rather than “recommend,” medical marijuana. This language creates additional risks for participating Texas physicians but also demonstrates an increasingly widespread view that federal pot rules are all talk and no action.

Instead of crushing the cannabis industry, Sessions’s ruling is likely to have a subtle chilling effect. Moderate lawmakers might be less willing to bet on cannabis reform — sorry, Texas — and investors will be more skittish about pouring money into canna-businesses. Sessions’s Department of Justice might even try for some high-publicity arrests. In the end, though, cannabis has come too far to be pushed back into the black market.

After Sessions’s ruling, NisonCo, a marijuana public relations firm, sent out statements from 11 cannabis entrepreneurs. Though few seemed to pleased with the new guidelines, none seemed terrified, either. “This is another expected bump in the road,” said Leslie Bocskor, president of Electrum Partners, a cannabis advisory and investment business. “This is an opportunity.”