On Thursday, White House Press Secretary Sean Spicer hinted at a shift in the way the Department of Justice will enforce marijuana laws, particularly in states that have legalized the drug for recreational use.

Spicer told reporters that while Trump views medicinal marijuana in a favorable light, he believes recreational use is linked to the opioid epidemic currently ravishing portions of the country. While there is no evidence for this claim, it spells a potential showdown between the Trump Administration and a number of states, like Oregon and Colorado, over recreational marijuana use.

“I do believe that you’ll see greater enforcement,” Spicer told reporters, before adding that the determination will ultimately be up to the Department of Justice.

Attorney General Jeff Sessions hinted at a similar shift during his confirmation hearing. When asked by Democratic Sen. Patrick Leahy of Vermont about his stance on states with loosened marijuana restrictions, Sessions responded by carefully not ruling out increased enforcement.

“Using good judgment about how to handle these cases will be a responsibility of mine,” he said. “I know it won’t be an easy decision, but I will try to do my duty in a fair and just way.”

A fight over recreational marijuana would bring the Trump administration into some very muddy political territory. Eight states have outright legalized the drug for recreational use. And nine states, including New York, Mississippi, and Rhode Island, have decriminalized the possession of marijuana. This means that, like with the Affordable Care Act, the Trump administration could find itself in the business of actively taking something away from Americans.

“These comments leave doubt and uncertainty for the marijuana industry, stifling job growth in my state,” Rep. Jared Polis (D-Colorado) told USA Today. “The public has spoken on recreational marijuana, we’ve seen it work in Colorado, and now is the time to lift the federal prohibition.”

Stefan Borst-Censullo, counsel to Hoban Law Group, a cannabis-focused law firm, says a fight with the now-booming marijuana industry would be a losing battle for the Trump administration. “Jeff Sessions is a terrible litigator who is taking on an enormously popular policy,” Censullo wrote in an email. “The cannabis industry has a base of well-funded supporters who are just as politically involved as folks in the NRA. Here in California, we can count on organized labor, public health advocates, law enforcement agencies, and Gov. Jerry Brown as our most strenuous supporters. If Trump wants to start a war on marijuana in 2017, bring it on.”

The financial interest in marijuana is sure to prove a significant hurdle for the president. The weed business is estimated to have netted over $1 billion in sales in Colorado last year, and a significant lobbying apparatus has emerged around the industry. According to analysis from New Frontier Data, which tracks the legal cannabis industry in the U.S., legal marijuana is set to create roughly 250,000 new jobs and will be responsible for $24 billion in sales by 2020.

“If Trump wants to start a war on marijuana in 2017, bring it on.”

Trump’s biggest challenge, however, might come from his base. Unlike the panicked suburbanites of the 1980s, whom Ronald Reagan successfully convinced to support a war on drugs, today’s landscape looks much different. According to a poll conducted by CBS News last year, 70 percent of Republicans believed that marijuana laws should be “left to each individual state government to decide.” Republicans, in general, still favor the general prohibition of marijuana, with only 43 percent believing that the drug should be legal. But more moderate Republicans favor legalization. According to a survey conducted by the Pew Research Center, 63 percent of moderate to liberal Republicans favor legalization. According to a Quinnipiac University poll from this month, 59 percent of all Americans think marijuana “should be made legal in the United States.”

It remains to be seen just how rigorous the administration’s enforcement of marijuana laws will be. The silver lining of a messy fight over marijuana might just be that it forces the federal government to act. For years, advocates have pushed for the legalization of cannabis on the federal level, and a public fight over the states that have chosen to legalize might be the way we finally get there.