A marijuana leaf is displayed at Canna Pi medical marijuana dispensary in Seattle. (Anthony Bolante/Reuters)

Sam Kamin is the Vicente Sederberg professor of marijuana law and policy at the University of Denver.

Nov. 8 was both the best of nights and the worst of nights for marijuana law reformers. That night, four states approved medical marijuana laws and another four voted to legalize marijuana use for all adults. But for many advocates, Donald Trump’s election served a substantial blow to law reform.

With Trump’s appointment of Jeff Sessions — one of the nation’s most outspoken anti-drug warriors — as attorney general, it seems the long-simmering tension between state marijuana law reform and federal prohibition is headed for a full-blown confrontation. It’s not surprising, then, that White House press secretary Sean Spicer attracted enormous attention last week when he appeared to presage a federal crackdown on marijuana law reform in the states — which would reverse the lax policy on marijuana set by the Obama administration.

Spicer’s comments are a perfect encapsulation of both the complicated state of marijuana law in the United States and the frenetic first weeks of the Trump administration. He stated that while the president is sympathetic toward those who use marijuana for serious ailments, the recreational use of cannabis is a different issue deserving of federal attention. As a matter of federal law, this distinction between medical and recreational use of marijuana is nonsensical.

Congress, in its wisdom, has classified marijuana as a Schedule I drug, alongside heroin and LSD. By definition, Schedule I drugs have no accepted medical use and a high potential for abuse; as a result their production and sale are prohibited nationwide, regardless of state laws to the contrary. Thus, if the new administration is serious about making marijuana available to medical patients, it could reschedule marijuana to make its use legal by patients around the country. Currently, medical users of marijuana are in violation of federal law, putting their employment, access to government benefits and parental rights at risk even in the absence of a federal crackdown.

Spicer also expressed the view that, in light of the opiate crisis facing the country, it would send the wrong message for the federal government to retreat from the enforcement of its own drug laws. But this grossly simplifies (and perhaps even inverts) the relationship between marijuana and more powerful drugs such as opiates. While marijuana has long been derided as a gateway drug, growing evidence shows that marijuana can serve as a substitute for or adjunct to the use of opiates to control chronic pain. In short, the opiate crisis might be a reason to expand access to marijuana rather than to contract it.

Moreover, the power of the federal government to enforce its own laws against marijuana production and sale in the states is necessarily limited. Much as Immigration and Customs Enforcement cannot simply remove all 11 million people who are in the country without authorization, the Drug Enforcement Administration lacks the resources to prosecute all those in violation of federal marijuana laws. It is for this reason that the federal government has historically relied on the states to do the lion’s share of drug enforcement. With a majority of states now opting to regulate marijuana rather than to prohibit it entirely, however, the federal government is confronting the practical limits of federal prohibition.

This does not mean, of course, that the federal government cannot make the lives of marijuana users, regulators and businesses difficult through threats, prosecutions and harassment. Much as ICE raids have terrorized more than just the “bad dudes” that the Trump administration claims to be targeting, increased use of law enforcement against those acting in compliance with state marijuana laws could have the effect of chilling much of the the medical use of marijuana that the administration says it supports.

It may be some time before we know whether Spicer’s statements were the announcement of a new policy direction, a trial balloon or simply off-the-cuff musings. But they highlight the need for nuance in this policy area. The administration needs to work with the public health community, law enforcement, Congress and state regulatory officials to create policy that is informed by both experience and data.

In normal times, a crackdown against an activity increasingly popular in the states and supported by large majorities of Americans would be a low priority for a new administration and would proceed only with care and deliberation. As the past month has made clear, however, these are not normal times.