I'd nominate Ferre.
To be honest, though, if we did organize a human collective more powerful than any nation, it would probably be powerful enough that even a group of nations wouldn't be enough to stand against us. We would undoubtedly have several citizens from those opposing countries within our ranks. Ever try to fight an enemy within?
I'm not so sure we'd need a president, either. Perhaps just a spokesperson, a public face, who simply informs us of our collective decisions. Maybe there's enough of us on the net, fed up with governments of nations dictating the course of history for us.