It happened in 2013 and 2014 with two times of FBI actions and seized bitcoin on Silk Road, then shut it down.
Not all of his statements will be executed after his Inaguaration in coming days. There are many things and barriers against many of his great ideas and ambitious plans including his intention to build up a National Bitcoin Reserve for the USA.
Regarding the Bitcoin reserve, I have my doubts whether or not it's going to be implemented. I believe Trump wasn't actually supporting the idea of cryptocurrencies, perhaps he has changed his mindset but I doubt he's going to implement such significant changes. To be honest, I'd rather he fullfil other more important promises.