I don't see why either side would object to this. Democrats keep saying that their political nirvana is a country with higher federal taxes, more federal regulations and more federal government spending. Well, let them have it! If they had a decisive political majority in a country that's half of America, they could have all of that -- and more. How could they possibly complain?
Same goes for the Republicans. They want fewer federal taxes, less federal spending and less federal regulation. Divide the country into two, and they could have it all. I don't hear a single Republican who would complain.
How would this work, practically? One party could have no more than 25 of the current states, where a minimum of 23 would be geographically consecutive, assuming the same entity also had Hawaii and Alaska. It would probably have to leave room for each half having at least one state on each of the two oceans. Practically speaking, that would, in turn, mean that California and Washington state could not be part of the same country -- the question is which would be which. Other than that, almost every combination would be possible.
Clearly, this would have to entail moving, for close to half of the population. The real solution here would be one of natural selection, where people would do it over some period of time. Americans moved before, such as in the 1800s when they headed West, and they still move today where some states show large net immigration numbers and other states have been de-populating for at least a decade or two. With more change and distinction, chances are that this new migration would be faster and more pronounced.
Big Enough to Split
The U.S. today is one of the world's largest countries, geographically. Our population density is relatively low. In other words, we have the luxury of doing this. Even in our smaller and oldest states in the Northeast, natural resources are vast and not cramped by most international standards.
This type of change would be difficult in the Netherlands or Austria. There is neither the population nor the land mass to support a split with great ease. That said, keeping a country together that's filled with division is also a great peril. Just look at the former Yugoslavia, where the only solution was to divide it into several tiny countries, in order to end a bloody civil war.
We won't want any civil war of any kind, let alone any bloodshed. We want a peaceful and amicable separation that will greatly satisfy both political sides of the spectrum. I hear from Democrats all the time that they would prefer that Texas go off and be its own country, because it is just not like the rest of 'em. Likewise, I hear political activists from other states say the corresponding same thing about California and Washington, D.C. With a peaceful and amicable separation, problem solved.
All of these political scores could be settled once and for all by both political sides to enjoy relative peace in each of their homes. We don't need a one-size-fits-all. We can have our cookies and eat them too. Just split the cookie in half.