The genie is out of the bottle, you can't just undo the last year of progress and knowledge. Even if the US took this drastic step, there will be other countries that will push forward. Or private interests. Or well-funded terrorist organizations. Etc, etc, you get the point. Much better, in my opinion, to stay ahead of the curve and tackle whatever issues head-on rather than burying your head in the sand, hoping for the best, and pulling out the surprised Pikachu face when someone else inevitably pushes state of the art forward.