Governments can issue regulations as they please. No doubt about it.
The promise of Bitcoin was to leave governments unable to enforce any kind of regulations using technology and decentralization.
The problem with that promise is that it is enormously expensive for consumers to run Bitcoin nodes. Therefore everyone uses third parties, there's not that many of them and there's absolutely no way for them to stay resistent to regulations.
So as I see it, there was a time when governments couldn't enforce their regulations to decentralized currency. Now they can.
What do you think? Is the Bitcoin promise broken?
Any government on different countries has the power to ban or stop the regulation of bitcoin. But bitcoin has the power to bypass those rules that is why some other countries can't completely stop the bitcoin in terms of doing transaction. What government can do is that put some fine when someone uses bitcoin in their country. But for sure, bitcoin will bypass it again since it is hard to trace.