The Trump Administration and Marijuana
As a defense attorney in Boulder, the legalization of recreational marijuana in Colorado affects many of my clients: some people use it for medicinal purposes, others work in the marijuana retail industry, and other people use it recreationally. However, marijuana is still illegal under Federal law. The Obama administration largely did not enforce marijuana laws in states where it was legalized. But the soon-to-be-confirmed Attorney General Sessions has been a vocal critic of legal marijuana, and left open the door to whether or not his office would increase prosecutions of marijuana-related crimes. So, as of this moment, we don't know how the federal government will approach and interact with states that have legalized recreational marijuana.
So could the federal government prosecute you, even if Colorado does not? Technically, yes. The federal government can bring criminal charges even when a state does not. However, is it likely that federal agents will jump out from behind the bushes to ambush the average person who walks out of a retail weed shop? No. The groups who are more concerned about the new administration are those in the marijuana business, especially as these businesses look to expand to other states. As an attorney in Boulder, I would advise anyone in the marijuana industry, or anyone looking to get involved in the marijuana industry, to consult with an attorney about potential risks and consequences and how to protect themselves and their business going forward.