They already failed when they used the mainstream media to bad-mouth Bitcoin and the result was not good for them as the people wanted to know more about it after hearing it from them. All they can do now is put some taxes on the holders especially those exchanges located in their countries. Those holders who have lots of Bitcoin in their wallets won't get any damage from government threats unless they move their BTC to the exchanges. As long as it stays on their hard wallet no one will know about it.