The Democrats are pushing for it. They are making a fuss in the Senate right now about a bill to prevent gun sales to anyone on the FBI's no-fly list. Scary. The FBI runs the no-fly list. They can put anyone on it, no evidence required. There is no way to get off it. Once on, you are stuck on.
Right now, only conviction by a judge in a real court, with a jury, a defense lawyer, and an appeal process gets you on the cannot-buy-firearms list. The Democrats want to hand that authority down to rank and file FBI agents. I think that's a bad idea. We ought to leave citizen's rights with the courts, not the cops.
Democrats love the idea.