One of the most troubling features of our current political and social climate is how powerfully it is shaped by sheer animus.
A couple of years ago, Scott Alexander wrote a post titled “I Can Tolerate Anything Except the Outgroup.”  I strongly recommend that you read the whole thing, but essentially Alexander sets out to answer a question: How is it that, say, straight white men can be gracious and kind to, say, lesbian black women while being unremittingly bitter towards other straight white men? What has happened here to the old distinction between ingroups and outgroups? His answer is that “outgroups may be the people who look exactly like you, and scary foreigner types can become the in-group on a moment’s notice when it seems convenient.”
Then Alexander gives a powerful example. He mentions being chastised by readers who thought he was “uncomplicatedly happy” when he expressed relief that Osama bin Laden was dead.
Of the “intelligent, reasoned, and thoughtful” people I knew, the overwhelming emotion was conspicuous disgust that other people could be happy about his death. I hastily backtracked and said I wasn’t happy per se, just surprised and relieved that all of this was finally behind us. […]
Then a few years later, Margaret Thatcher died. And on my Facebook wall – made of these same “intelligent, reasoned, and thoughtful” people – the most common response was to quote some portion of the song “Ding Dong, The Witch Is Dead”. Another popular response was to link the videos of British people spontaneously throwing parties in the street, with comments like “I wish I was there so I could join in.” From this exact same group of people, not a single expression of disgust or a “c’mon, guys, we’re all human beings here.”
Even when he pointed this out, none of his readers saw a problem with their joy in Thatcher’s death. And that’s when Alexander realized that “if you’re part of the Blue Tribe, then your outgroup isn’t al-Qaeda, or Muslims, or blacks, or gays, or transpeople, or Jews, or atheists – it’s the Red Tribe.”
Since Alexander wrote that post, an article has appeared based on research that confirms his hypothesis. “Fear and Loathing across Party Lines: New Evidence on Group Polarization,”  by Shanto Iyengar and Sean J. Westwood, indicates that Americans today do not simply feel animus towards those who disagree with with politically, but are prepared to act on it. Their research discovers a good deal of racial prejudice, which is to be expected and which is likely to grow worse in the coming years , but people seem to think that they shouldn’t be racists or at least shouldn’t show it. However, people of one Tribe evidently believe, quite openly, that members of the other Tribe deserve whatever nastiness comes to them — and are willing to help dish out the nastiness themselves. “Despite lingering negative attitudes toward African Americans, social norms appear to suppress racial discrimination, but there is no such reluctance to discriminate based on partisan affiliation.”
That is, many Americans are happy to treat other people unfairly if those other people belong to the alien Tribe. And — this is perhaps the most telling finding of all — their desire to punish the outgroup is significantly stronger than their desire to support the ingroup. Through a series of games, Iyengar and Westwood discovered that “Outgroup animosity is more consequential than favoritism for the ingroup.”
One of my consistent themes over the years — see, for instance, here  and here  — has been the importance of acting politically with the awareness that people who agree with you won’t always be in charge. That is, I believe that it is reasonable and wise, in a democratic social order, to make a commitment to proceduralism: to agree with my political adversaries to abide by the same rules. That belief is on its way to being comprehensively rejected by the American people, in favor of a different model: Error has no rights.
What is being forgotten in this rush to punish the outgroup is a wise word put forth long ago by Orestes Brownson : “Error has no rights, but the man who errs has equal rights with him who errs not.”