Let's extend that obvious line of thought: what would the basis of this division be? What about the benefits reaped from the heterogenous nature of giant count

Let's extend that obvious line of thought: what would the basis of this division be? What about the benefits reaped from the heterogenous nature of giant countries like USA? Are you willing to give all that up for this single goal? All said and done, I strongly believe USA as it is moves the humanity forward considerably in the mid-long outlook. Hence my questions.