Dunno about the USD and the Americans, but in Germany it's already officially legal and they've updated their tax stuff so they can easily tax businesses getting revenue from it.
You need to understand that not everyone into bitcoin is into anarchy and all that political stuff.
The Germans (famous for being statists) simply see it as a clever new technology that is secure and efficient, with benefits that the current technlogy for transferring money doesn't have. Because it's non-political you get take-up both from left-wing hippie types in Berlin who hate dealing with banks, and the capitalists in Frankfurt who think this might be an exciting new asset that won't be manipulated like gold currently is.
(There's a lesson there for Americans - don't politicize bitcoin if you want maximum take-up)
As for Britain - the banks are nervous, but the govt is toying with licencing one of the big existing forex exchanges to trade bitcoin on the grounds that a) it's here, and b) if it's here we might as well allow trade, because London makes it's money on fees from being the premier trading centre where you can buy and sell anything.
So bitcoin isn't going to disappear on this side of the Atlantic. I'd be surprised if teh Americans tried to halt it either - all those silicon valley types will lobby against the bank types who want the status quo - and the Valley boys may have more clout.