1. The loophole to get marijuana legalization implemented has only partly worked so far. It's currently legal to grow and own marijuana, but not to sell it. Originally the plan was to have the sales of marijuana be regulated, but congressional meddling has frustrated those efforts so far (some possible solutions have been tossed about; we'll see if any work).

2. Statehood wouldn't require a constitutional amendment. The most recent statehood bill, S. 132, envisions shrinking the area of the Federal District to be just the area around the federal buildings, and creating a new state out of the area where the hundreds of thousands of D.C. residents live. We "only" need to get the bill passed by both houses and signed into law to get statehood. So if Dems control both houses and the presidency again (and we have filibuster reform, or a super-majority), then it shouldn't be too difficult to get statehood.