Biden only supported legalized medical marijuana, and to his credit, he did actually start the process to do that. He order rescheduling to schedule 3 which basically legalizes medical marijuana. It should go into effect around December as the DEA has dragged out the process
I mean Biden has already started the process for rescheduling weed to schedule 3 for medical legalization. Process is long but it's at the tail end with the final hearing in December. It's not too hard to see Harris just using the same process but asking for full descheduling rather than asking them for schedule 3. Or if Dems get a trifecta, she could also try to get congress to legalize directly in law (faster than the executive branch only action)