While neither the Republican Party nor the Democratic Party have fully supported legalized marijuana, the Democrats are usually more supportive of the issue than the GOP. But when it comes to political donations, the Republicans are getting all the rewards.
According to USA Today, the vast majority of political donations made by the cannabis industry in recent months went to Republican politicians. While Democrats have usually been favored by the industry, in the past year there's been a switch towards giving money to more conservative candidates.
The reasoning behind this move isn't entirely clear. USA Today says that cannabis companies see pro-states rights Republicans as being their best allies in the fight for legalization, but that seems half-baked. The GOP is pretty divided on the issue, and even if pro-states rights Republicans support legalization, you'd still need Democrats' help to overcome the anti-marijuana GOPers.
A more plausible explanation would be that Republicans control the federal government entirely at the moment. The White House, House of Representatives and Senate are all dominated by the GOP. Since they're the ones in control of setting the legislative agenda, supporting them makes sense for the cannabis industry. Although they run the risk of losing support among Democrats if they're able to retake either the House or Senate next November.
It should also be noted that while there's been an increase in the amount of money donated by the industry, it's still a relatively small amount compared to other industries. USA Today noted that the largest marijuana advocacy and industry groups have combined for $327,000 in donations over the last three congressional election cycles. In comparison the National Beer Wholesalers Association donated $1.5 million to candidates in 2017 alone.
The cannabis industry is trying to become a player in the national politics scene, but it remains to be seen how much their influence (and their money) will be able to actually change things.
(h/t USA Today)