And even if they did ban BTC through any form of legislation, including an executive order, what would it actually result in in terms of enforceability? Probably absolutely nothing, given the fact that bitcoin is decentralized.
If this was possible, then countries would have done it long ago - they are not stupid.
You'll find that the threat of jail time is more than enough to dissuade a lot of users. Hardcore users will continue what they're doing, but keep in mind that this will also hurt user experience -- no more exchanges, businesses can't accept crypto payments, etc. The fact that Bitcoin prices have a tendency to run on news (and one of the biggest and most active markets being shut down would be
bad) could also lead to prices plummeting. Bitcoin won't die, but a move that drastic would undo several years worth of community development.
Either way, know that BTC can survive without the support of any central entity, as demonstrated by the bull run after China essentially banned all miners and exchanges.
China backed off the mining ban, and they still let OTC exchanges operate.
As for the topic itself, Trump has already banned Petro with an executive order, which is more closely related to Bitcoin than e-cigarettes are. Does that mean we should be scared?