However, banning bitcoin in any democratic country will be extremely difficult. Bitcoin's decentralized approach to currency is very people-centric and as it becomes more mainstream, more people will understand its benefit. Any democratic government that bans something so beneficial for the people risks losing power.
Banning bitcoin is pretty easy even in democratic country, because Bitcoin users are just a tiny minority and a lot of people haven't even heard about it. Take for example weed - 52% of Americans over 18 have tried it at least once, yet the government wages war on it. And although it's impossible to kill Bitcoin, they can certainly hurt it - if they will go after miners, which is very easy to do with their giant power consumption, we will lose the hashpower that secures current value of transactions in blocks, and they can even turn that hashpower against us if they will use seized mines to attack the network. ISP's might try to block or slow down all Bitcoin-related traffic, so we will have to use Tor, which will have negative impact on block propagation speed. Buying at selling Bitcoin would also be pretty hard if it will be outlawed, meaning less liquidity. To sum it up, lets just hope that it won't be outlawed by any major government.