At the early stages Russia ruled it as illegal, China outlawed all withdrawals and some other country also spoke against it. But now everything seem to be smoothing up at least on the government side. Surely Bitcoin must be seen as challenging their authority. Is there something I am failing to see? All it would take is a 51% attack or a new law.
it is impossible for the government to block the Bitcoin ecosystem, including the activities of digging bitcoin (mining). just block the buying and selling sites and prohibit the development of a Bitcoin payment platform for expenditure. It also is a futile effort, because users will find a way to monetize Bitcoin or use it to transact.