Yes. They can go against it if they want to or if the situation arises and they need to take action.
Bitcoin is like an enemy to a country. It disturbs their economic balance and the more people who use it, the more likely it will go out of control in government perspectives. Also, there's a thing about its security being anonymous, leading to more and more people doing illegal transactions easily with the use of this digital currency. Other countries solution was to make the use of bitcoin illegal or restricted. This is their way of taking control the overall happenings in their country.

But I have heard that many countries are starting to accept and embrace bitcoin.
Anyways, I am just glad that our country is still not taking actions involving cryptocurrencies.