Bitcoin has no centre to attack. There is no single organisation or person that controls Bitcoin and transactions don't go through a central clearing house there is really no way a regulator can stop people from downloading Bitcoin wallets and sending each other bitcoins. Government can only use media as a weapon.
Yes You are right the government can do any think. because there are find any think about bitcoin. bitcoin will be stop if the miner stop mining. but the are not possible. government only what happen and what will doing bitcoin. then new revelation in currency world.