I believe that in the years to come, major governments, such as the US government, will (or perhaps have already) come to the conclusion that trying to make bitcoin illegal would be starting another currency war which they are not sure to win, as bitcoin doesn't really need to be "made legal" to exist, and because it poses many legal challenges that they are not ready to confront, such as the fact that bitcoin isn't legally money, etc.

BUT...

the US government (among others) will probably try to TAX all virtual currencies (and particularly bitcoin), and this new tax could make exchanges operating in the US unprofitable, which would drive them out of the US. Then they could try to use their influence to try to persuade other countries to do the same.

However, I believe that this will ultimately fail, too. But it could do some damage to the BTC exchange rates in the years to come.

Any idea on this?