Today, Attorney General Jeff Sessions is expected to announce that the Department of Justice will rescind a policy that had previously allowed legal marijuana to expand in the states with limited interference from the federal government.

The policy, often referred to as the Cole memo, was implemented under the Obama administration and advised US attorneys that “In jurisdictions that have enacted laws legalizing marijuana in some form and that have also implemented strong and effective regulatory and enforcement systems,” enforcement of federal law related to marijuana would not be a priority. While marijuana was still illegal under federal law, the Department of Justice would not generally disrupt the implementation of state marijuana law unless there was a compelling reason.

This laissez-faire approach allowed the legalization of both medical and recreational marijuana in the states to grow without being challenged by the federal government. By abandoning the policy outlined in the Cole memo, Attorney General Sessions is now giving US attorneys the freedom to begin prosecuting people who violate the federal prohibition on marijuana, regardless of state law.

US States that Have Legalized Marijuana (Medical and/or Recreational)

This reversal comes just days after California implemented the selling of recreational marijuana, which was voted into law in November 2016. While other states have also legalized marijuana for recreational use, California was seen as a watershed moment for marijuana policy because of its size; due to California’s population and economy, it became the largest market for legal recreational marijuana use in the country. According to predictions by the Agricultural Issues Center at the University of California, Davis, legalized recreational marijuana could add $5 billion a year to the California economy.

Massachusetts and Maine are poised to implement their recreational marijuana legislation in 2018 (approved by referendum in 2016 by 53% and 50.3%, respectively), while states like New Jersey, Michigan, and Vermont were expected to consider the issue sometime this year. A majority of the states will be impacted by this decision, adding fuel to a potential federalism showdown.

The decision by Attorney General Sessions to abandon the strategy outlined in the Cole memo does not come as a surprise, as Sessions has been a longtime opponent of marijuana, famously saying that “good people don’t smoke marijuana.”

However, for now, Sessions’ announcement today puts the power in the hands of US attorneys, who will ultimately have the discretion on whether to seek prosecution of those who violate federal drug law. This may result in even more confusion in marijuana policy, as some US attorneys may decide to prosecute, while others may not. For an industry that already has uncertainty due to federal law, this could potentially introduce more chaos to the mix.