This is the way I belive it is going(gimme a break, I'm not saying tomorrow either) :
We will have a central governmental body, call it Earth one if you want to, which coordinates and updates the autonomous regional areas under it. No way of telling how many areas, or what criteria they will be classed under, but specialisation of production will be fact so it is likely that the new sectors(that will be unbound to current nations)will be constructed according to that.
How the governing itself is done is impossible to guess. It will not be a democrasy as that ceases to work properly once you get enough people ruled by it(there's just too many that are not satisfied, by sheer numbers). Likely, to my mind, is a some sort of beurocratic technocrasy.
there will be no nations as they are known today, and it IS likely that a new pan-religious philosohpy will replace most of the older religions as information becomes ever more readily available.
We might blow up ourselves first, but if we don't then this is what I belive will happen(more or less). For this to be a good thing free information is a MUST.
Once every part of the planet is dependent on every other part for survival and growth, war between any part of it and any other part will be far too costly to contemplate seriously for anyone but the Religiously or philosophically motivated. These people, willing to take up arms for these reasons, will never become anything other than a minor neusance as there is heavy economic incentive to prevent such things.
Who would this government hold the people for ransom to? What Ransom would they be asking? And why would it not be seen and stopped if the two first were somehow provided? I did mention free information as part of the equation here.
Again, I belive there is little point in my having written this. But by all means, go ahead