Over the last twenty-four hours, three events have brightened the prospects for marijuana legalization. First, three states passed pro-marijuana referendum initiatives. The crucial purple state of Michigan became the tenth state to legalize recreational marijuana. Socially conservative red states Missouri and Utah became the latest of 33 states to legalize medical marijuana - the latter despite the strong opposition of the LDS Church. The defeat of a legalization initiative in the relatively small state of North Dakota is a minor setback compared to the three victories. Second, the Democratic takeover of the House of Representatives ensures that there is now a strong House majority in favor of abolishing the federal law banning marijuana. The overwhelming majority of congressional Democrats favor such a move, as do a substantial number of Republicans. Finally, President Trump's abrupt dismissal of Attorney General Jeff Sessions - although unrelated to his championing of the War on Drugs and his many other awful policies - removes the most important opponent of marijuana legalization within the executive branch. It was Sessions who sought to escalate the federal war on marijuana earlier this year, when he terminated an Obama-era policy discouraging prosecution of marijuana producers in states that had legalized pot under state law.
The combination of these three developments significantly increase the chance that Congress might finally abolish or at least severely curtail federal marijuana prohibition in the relatively near future. Earlier this year, Colorado GOP Senator Cory Gardner cut a deal with Trump under which the latter would potentially back the elimination of federal prohibition in states that had legalized marijuana under their own laws. In June, Gardner and Democratic Senator Elizabeth Warren proposed the STATES Act, which would do exactly that. So far, the bill has made little progress. But it or something like it would have a better chance next year. A Democratic-controlled House could pass it without having to worry about the Hastert Rule or potential opposition from socially conservative Republicans who still favor federal prohibition.
The GOP's net gain of two or three seats in the Senate (at this point it is not clear who will prevail in the close race in Arizona) could potentially make passage harder in that chamber. But Gardner would only need a handful of GOP votes (in addition to his own) to get a bill like the STATES Act over the top. And there is a good chance that several other GOP senators might support it on some combination of federalist and libertarian grounds. Eliminating federal prohibition would be an important success for constitutional federalism as well as legalization. Senate Majority Leader Mitch McConnell is unlikely to go to the mat to oppose such a bill, especially given his own enthusiasm for hemp.
Federal marijuana legalization is not yet a done deal. Various factors could still derail it. Even if it does happen, there is still a long way to go on curbing the broader War on Drugs, which inflicts far greater harm than marijuana prohibition alone. Still, prospects for legalization are definitely looking up.
UPDATE: Jacob Sullum makes some related points in this piece, including noting the significance of the defeat of GOP Rep. Pete Sessions (no relation to Jeff, but a fellow influential drug warrior nonetheless).