There's a funny bit of history about this book: it was written in 2005-6 as an explanation of how President Bush won a landslide election and how Republicans had built an insurmountable, generational majority.
Far from being an anachronism, the emerging American geopolitics and new electoral strategy outlined in this book were adopted by every presidential campaign since. The Big Sort-era election winners each won with strategically similar campaign. Bush, Obama, and Trump are eerily similar. They eschewed political persuasion or classic triangulation (playing to fringe in the primary and the center in the general). Each campaign's paramount goal was getting their own geopolitical tribe to vote. And, on the other hand, the best explanations for the failed campaigns of McCain, Romney, and Clinton remains under-motivating their voters.
In the Big Sort era, all attempts at political persuasion of the undecided or the moderate are electoral malpractice. Political campaigns are now such a team sport that one doesn't even need to take the same field: each side gins up their own people in their own areas. The vote counting, below the presidential level, tends to be predetermined by where the election is being held.
Why? From presidential to local elections, a large part of the partisan decision is made the city, county, or district lines around the voters. Some places are so politically similar, that no lines can be drawn to make a district anything close to 50/50. People live in places with others who vote like them. And they signal to the other tribe that they aren't welcome. If you're in a Whole Foods, there's something like a 90% likelihood that the surrounding county voted for the last Democratic candidate for president.
Especially striking was the story of the author's neighborhood email list in his posh Austin neighborhood (deep blue city, bright red state). The lone Republican in the mix was publicly shamed for daring to voice dissent to the neighborhood's 2004 election protest. Imagine that: liberals being intolerant! I must set my smugness aside: daring to support a Democrat will get you run out of most suburban evangelical churches. This is American geopolitics, and it's tribal.
The real question is what do we do about the big sort? This book didn't have much.
I have moved away from Republican places twice. As a usually-Republican voter, my peregrinations are the 1 or 2 out of 10 (the other 8 moved to areas with similar voters). The exurbs of DC and ATL held no attraction for me, despite them being homogeneously rich, with large backyards and loose gun laws. I like much better the liberal cities of Portsmouth, Washington, and (now) greater-Boston. Perhaps I'm a genetically disfigured conservative, more open to new experiences and living in close quarters with neighbors. Maybe I'm a secret liberal!
The story of one doesn't undermine the data of the big sort: more people than not move to places where their neighbors share their politics. How can we combat this regional tribalism? Maybe we can all take a road or train trip to the other side of the line and learn how the other half lives. That is, if we can find decent eats.