Easily be stopped? Hardly. You have to realize that the government is slow to react. Even if the US outlaws bitcoins or another countries does then there are still 200+ other countries where it is legal.
Easily. If there is one persistent fallacy that is repeated over and over again on these forums, that needs to be put to rest it's this "Bitcoin is unstoppable" and "we don't need anyone" foolishness. The Developers don't think it's unstoppable- and they know the code back to front.
If Bitcoin is not unstoppable from a technical point of view, then it's already dead in the water. Has anyone really claimed this?