You're kidding right? The DEA has busted and shut down dozens of legal medical marijuana dispensaries over the last few years in every state that has legalized it, including right here in good old "liberal" California. As with so many other things that Obama promised, what he says and what he does are two completely different things. Kind of like "if you like your coverage, you can keep your coverage".
Trump hasn't done a 180 on marijuana. He once said in the 90's that he felt all drugs should be legalized, taxed, and controlled. He now sees what has happened in some states like Colorado and has changed his mind about legalizing marijuana federally, but feels that states should still have the right to approve it if they want without federal intervention. He also still feels that "medical" marijuana should be completely legal when prescribed by a doctor.
https://greenrushinvestors.com/donald-trump/