As you know,btc is like the internet of money.  If it is declared illegal within any country then businesses and bitcoin exchanges will have to shut shop in the region only. Being a global phenomenon it cannot be banned throughout the world.
Like the internet, bitcoin as a whole cannot be regulated/censored/made illegal as it is not constrained within the borders of one nation. Businesses based on the idea of bitcoin can be subjected to regulation but the whole network itself cannot be.