The “Great Sort” of Americans into ultra-defined geographies based on political beliefs is intensifying, according to The Hill:

 As the American electorate grows more diverse, and as a rising generation of millennials begins supplanting formerly dominant baby boomers, two nations that live side by side are increasingly walling themselves off from each other.

That divide is a conscious choice, one that experts say influences how we interact with each other, where we move, what news we consume and, increasingly, how we vote.

This developing chasm in political ideologies is a major driver of the tactics used by candidates for federal office, according to the new book, “Fixing Post-Truth Politics:”

Representatives in Congress respond more to their activist bases than to the median voter in the general election. This “force for polarization” means that both independent voters and members who reach across the aisle and compromise are nearly extinct.

The electorate’s growing partisan nature has coincided with a high degree of consistency in the results of recent elections. The 2012 presidential election saw the highest party loyalty in the history of the American National Election Study (conducted since 1948): 93 percent of Democrats voted for Obama and 93 percent of Republicans voted for Romney. The 2012 election also produced the lowest rate of ticket splitting, as 90 percent of Americans supported the same party for President and the House, 89 percent for President and the Senate, and 87 percent for the House and the Senate.

Voters are less inclined to support a centrist candidate than ever before, and the widening gap is staggering as shown in the battle for the presidential nomination in 2016. Candidates have more reason to appeal to their extreme supporters than to try to win independent voters as a pragmatic moderate.

The increasing divide between Red America and Blue America has sewn animosity and distrust among even the most patriotic among us as partisan echo chambers reinforce notions that those with ideas that run counter to our own are out for nefarious purposes, The Hill reported:

Much of those ill feelings come, experts say, because Americans have increasingly limited opportunities to interact with those on the other side of the political aisle, because Red America and Blue America look distinctly different and view the other with growing suspicion, and because the two have experienced vastly different recoveries after the Great Recession.

“Our demographics have become tethered to our partisanship in a way that wasn’t the case in much of the 20th century,” said Paul Taylor, a senior fellow at the Pew Research Center and author of “The Next America: Boomers, Millennials and the Looming Generational Showdown.” “It gives us the incredible ugliness of our politics in 2017.”

The sorting taking place now is based on a handful of factors: Rising birthrates and immigration among nonwhite communities mean urban America is growing faster than rural America. Young adults, who tend to be more liberal, are choosing to live among those who think and act as they do. And the internet has given us the ability not only to communicate with those who think like us, but also to find out where they live.

“Fixing Post-Truth Politics” points out that via the “sorting” phenomenon, the Democrats are a more homogeneously liberal party and the Republicans a more homogeneously conservative party compared to the 1970s, for example.

Particular values receive defense from only one of the two sides, and specific kinds of people seem to get a sympathetic hearing by only one of the two parties. The consequence is that the actions considered by government bodies are more likely to present stark choices today than in some earlier, less polarized, more civil eras. Therefore, elections matter more. As the stakes rise, civility falls.

While the lack of politeness and courtesy is very evident, it is not nearly as big of a problem as others we have outlined. These include outright lying, a government that cares little about true and false and right and wrong, and an electorate that no longer trusts the entity that is supposed to be their government watchdog, the free press.

Living among those who resemble us even extends online, The Hill reports:

Just 23 percent of the average person’s Facebook friends claim an opposing political ideology, according to the company’s internal research from 2015.

Read “Fixing Post-Truth Politics” for much more on this phenomenon and what it has meant to our political and cultural existence in the United States in recent years.