It is a primitive thing to jump to labelling your opponents in such a manner. Nobody can stand up to the American military without guerilla tactics, so America labels all its enemies "terrorists" and says they are all extremists who hate freedom and cannot be reckoned with. Before, it labelled its enemies "commies", and said they were against democracy and freedom, attaching all kinds of negative traits. If we go far enough back, it labelled all evil "the devil" in order to better visualize it as something as universally understandable as a person.
The only world government that could happen within ten or twenty years is America flipping out and trying to conquer the world, British Empire style. On a larger scale, maybe within a century, Europe might somehow ally with America peacefully, with Europe spreading eventually to admit western Russia, but that'd be quite some time away.