And we are getting increasingly different.
"Most Americans are very upset about what's going on," Haidt tells me in an interview.
The book cites Gallup polling showing that between 2000 and 2011, voters calling themselves "moderates" dropped from 40 percent to 36 percent, while "conservatives" rose from 38 percent to 41 percent and "liberals" rose from 19 percent to 21 percent.
In other words, only the political middle is losing ground.
Also, the percentage of folks living in "landslide counties" - those in which one party always wins by margins of 20 percent or higher - rose from 27 percent in 1976 to 48 percent in 2008.
In other words, the right and left are more set in their ways.
There's some demographic fun: If a community has a Whole Foods organic grocer, it voted for Obama in '08; if it has a Cracker Barrel Old Country Store & Restaurant, it voted for John McCain.
But the larger points Haidt makes are that our views are based more on moral intuition than finances, reason or even self-interest.
Extensive interviews on six "moral foundations" - caring, fairness, liberty, loyalty, authority and sanctity - help explain basic thinking on the right and left.
Both sides place high value on caring, fairness and liberty; although liberals are more into caring, conservatives more into fairness.
Conservatives are huge on loyalty, authority and sanctity; liberals ambivalent.
So conservatives offer a broader moral foundation and liberals need to crank up some moral precepts if they hope to achieve wider appeal.
Haidt argues that we all evolve as "tribal" and that politics is a competition among coalitions of tribes.
As such, things our tribes hold "sacred" define our stances on issues.
For liberals, the "sacred" can be minorities, women, gays, any victimized group.
For conservatives it can be the Founding Fathers, the family, the flag, the Bible.
So although liberals regard welfare and feminism as fighting against oppression, conservatives see them as threats to responsibility and family stability.
Obama's move to have religiously affiliated institutions pay for contraceptives outraged the Christian right and boosted (however briefly) Santorum's campaign.
When various legislatures moved to require women seeking abortions to first undergo ultrasounds, outrage on the left boosted (however briefly) Obama.
Both actions, and therefore both sides, were demonized.
Haidt thinks polarization continues because technology allows us "to live in gated moral communities . . . you can't desegregate morality."
The blogosphere, the increased role of money in campaigns, less civility in Congress, overzealous media on the left and right feeding overzealous activists on the left and right all detract from reasoned debate.
Would it kill Fox or MSNBC to have guests with differing views and treat them with respect? Too many "news" broadcasts are simply linear affirmations of one side or the other.
Haidt's book doesn't pretend to offer solutions, although his website civilpolitics.org has ideas. Instead, it argues that people who disagree aren't so much good or evil as wired to righteous beliefs within individual "tribes."
What he seeks are starting points of understanding, from which possibly things improve. It's a righteous effort. And The Righteous Mind is a worthwhile read.
For recent columns, go to
philly.com/JohnBaer. Read his blog at www.philly.com/BaerGrowls.
