With Democrats now in control of the White House and both branches of Congress, marijuana proponents say 2021 offers their best chance yet to end America’s longstanding national prohibition on the drug — or at least ease tight federal restrictions on cannabis research and banking for the legal pot industry.

But even advocates and marijuana business owners who have long demanded such reforms are eyeing the possibility of their implementation with decidedly mixed feelings.

That’s because a liberalization of federal cannabis laws — while it could reduce prosecutions, wipe away old marijuana convictions, and alleviate the many business headaches that come with selling a federally illegal product — threatens to massively disrupt state-regulated pot markets across the country.