The bicoastal distribution of liberalism is a result of Yankee migration out West, starting with Oregon and the Old Northwest, and the only partial acculturation of the Atlantic Slope "deferential society" (as historian T.R. Fehrenbach calls it, I haven't seen the phrase elsewhere but it works) to Middle American values. Others are simply still half-European and never really got off the boat, but were intercepted on the wharf by ward heelers who took charge of them.
My idea of a new Constitution, same as the old one, but with New England and downstate New York disinvited, would give us the political heft to invite the rest of the "New America" to emigrate to Uruguay or Paraguay, where the Gay Left is going to create a fabulous new society and show us all how it's done (instead of leeching off us and stealing people's kids).
"Deferential society"? Read your book again. What part of America was more deferential than the Tidewater and the Lowland South? Old Virginia? Charleston? New Englanders had a reputation for being unruly disturbers of the peace -- Roundhead regicides in the 17th century, Sons of Liberty and Minutemen in the 18th, Abolitionists and Transcendentalists in the 19th. At least that's what Southern militants said about New England before and after the Civil War.
Of course there were long periods when New England was one of the more conservative parts of the country (say from the 1880s to the 1950s). This indicates that it's not so easy to make generalizations about the political culture of different regions. Connecticut and Alabama or Vermont and Mississippi are almost always going to be on opposite sides of political fights at any given time, but the positions taken may differ widely from era to era.
Of course, Portland OR has more in common with Portland ME than with a lot of other places in between. But the main factor is (as you suggest) that cities tend to vote Democrat and rural areas vote Republican. States dominated by cities and urban ways vote Democrat. Southern cities tend to vote Democrat. Atlanta and Jackson MS, say, weren't that far behind Northern cities in their vote for Obama. But there are more rural voters in Southern states. I know that it's more complicated than that, but heavy urban support for Democrats puts a monkey wrench in your plan.
"Middle America"? Does that include regions settled by Germans, Scandinavians, Dutch, Czechs? You might be surprised at how "half-European" by your standards some of them may be. Certainly, you'd be surprised at how little enthusiasm many of them would have for your plan. If the country splits up, it splits up in a big way. Ohio and South Carolina, Idaho and Arkansas, or Iowa and Alabama may realize that they don't have that much in common and don't want to subject themselves to some government over on the other side of the continent.
The thing about "Middle America" or the "Silent Majority" is that it's people coming together against something. Take away that something and people on different sides of the country may find that they don't have that much in common. It's also people coming together for something, but if the country's being torn apart we might see just how weak that "something" binding different states to the union has become. None of the pieces would be able to play the kind of role the US does in the world today. On balance, that would probably be a bad thing.
Read my post again: I referred to the Atlantic Slope (East Coast), not New England only. European habits lingered longer all up and down the seaboard, even moreso among the jampacked cities full of immigrants.
I lost my earlier reply to you, but in it I did note that German immigrants, with their tradition of authoritarianism (which made Union men of them reflexively, when the Civil War began: government is God, all praise the government), did not settle in areas haunted by Jacksonians, but instead clustered with their own in northern Missouri, Nebraska, and Iowa. Those who went to Texas found out the hard way what public expressions of support for Unionism could get you there.
Of course there were long periods when New England was one of the more conservative parts of the country (say from the 1880s to the 1950s).
Of course they were "conservative" then: They'd won the Civil War (the gomers out West had no idea they'd lost, just like the South, except when they tried to transship their crops to market on Yankee-owned railroads), they were wallowing in the spoils of a continent, and they always had the Southern rednecks to eat .... and spit on. Life was good. Of course they were "conservative" -- they had it all, which was all the sweeter because those crackers down South had damn-all and were poorer than dirt. Yes, life was sweet.
Of course, Portland OR has more in common with Portland ME than with a lot of other places in between. But the main factor is (as you suggest) that cities tend to vote Democrat and rural areas vote Republican.
No, attitudes and values migrated west with the people who left the Eastern source-areas, an idea shown to be obvious by Kevin Phillips, who compiled a series of maps by issues and showed this phenomenon in color, in the process attracting the attention of Richard Nixon, who 15 years later gave Phillips a post in his first administration. Yes, there is an urban/rural component in many issues and value sets (the Communist Party and its NEA subsidiary have never taken much interest in organizing the rural demes), but the starting point is always the values imported by immigrants from the East.
If the country splits up, it splits up in a big way.
If it does, whose fault will that be but the 'Rats', with their constant subornation of the 47%? Certainly not the fault of conservatives. But if you think the country would blow apart if confronted by a constitutional convention, then you're certainly entitled to your opinion. I happen not to share it, but to think instead that most everyone in America not attending UC Berkeley knows who the troublemakers have been.