The one that cannot possibly be stopped? How are they going to "crack down on bitcoin"? Note how well the crack down on filesharing is going...
The difference between filesharing and BC is that in the former the value is in the files, but BC is only valuable if you can trade them for something you value.
Govt can crack down at any point where bitcoin is convertible into something that they can affect.
For example, they can stop many biz from accepting bitcoin.
Sure, you'll probably be able to buy foreign porn with bitcoin, but ....
> Note how well the crack down on filesharing is going...
That's a very different problem.