The Cole memo provided “guidance” for federal prosecutors, but since December 2014, a law has been in effect that blocks the Justice Department from spending resources prosecuting state-legal medical-marijuana businesses. Now known as the Rohrabacher–Blumenauer amendment, for two of legalization’s strongest supporters in Congress, it was renewed annually until November 2017, despite Sessions’ efforts to kill it. The next question is whether it will be renewed again with the spending bill that needs to pass by Jan. 19 to avoid a government shutdown.

Instead, during his first year as attorney general, Sessions has repeatedly tried to clear a path to crack down on the federally illegal drug.This has been more difficult than you might think for the nation’s top law enforcement official.

Sessions has sat out this remarkable shift in public opinion. In 2016, he said, “Good people don’t smoke marijuana.” By November 2017, his views had evolved slightly to acknowledge that marijuana is not as destructive as heroin. However, he remains skeptical about the plant’s medical uses and has not shown any outward interest in how much the politics of pot, and the facts on the ground, have changed since the “Just Say No” era.

As for medical marijuana, public support now hovers at about 90 percent. Veterans, a traditionally right-leaning demographic, are now among the most vocal advocates for medical-marijuana research. In particular, they want to see it studied as a therapy for PTSD and traumatic brain injury. There is also growing, and increasingly credible, interest in cannabis as an “exit drug” from opiate addiction. (FiveThirtyEight considers legalization is among the least polarizing issues in the country.)