Social scientists believe they know why America has become so divided along political lines. "The human brain in many circumstances is more suited to tribalism and conflict than to civility and reasoned debate," The Wall Street Journal reported last month in a piece headlined "Why Tribalism Took Over Our Politics."
Modern communication tools are especially able to exploit this finding, providing users with what they want to hear rather than challenging assumptions.
"Decades of social science research show that our need for collective belonging is forceful enough to reshape how we view facts and affect our voting decisions," the essay asserts. "When our group is threatened, we rise to its defense."
The Journal cites Donald Trump as a reliable practitioner of exploiting group identity, although it allows that Democrats also use the tactic, but "not as forcefully."
It's true that the former president's ardent supporters see themselves in similar terms as outsiders scorned by the elites. But the idea that Democrats only reluctantly appeal to this base instinct is laughable. The Democratic Party virtually invented the toxic notion of identity politics and has built entire coalitions on the idea that individuals are defined, not by their words or deeds, but by their skin color, sexual preference or any number of other characteristics.
In a memoir published shortly before his death in 2011, Christopher Hitchens tore into the concept, which he dated to the late 1960s.
"It would never have done for any of us to stand up and say that our sex or sexuality or pigmentation or disability were qualifications in themselves," he wrote. "There are many ways of dating the moment when the left lost or — I would prefer to say — discarded its moral advantage, but this was the first time that I was to see the sellout conducted so cheaply."
Yet this is the modus operandi of the modern Democratic Party, which has become openly hostile to concepts such as personal responsibility and individual liberty while promoting group identity and grievance. If Trump has become especially adept at practicing the politics of tribalism, he has had years to watch how it's done.
This obsession with identity politics has indeed led to more division and becomes self-perpetuating. "Americans in the past were more likely to meet people different than themselves," the Journal reported, "which created opportunities for reducing group bias and creating conditions for compromise."
But how do we turn back from this poisonous path? A Stanford study found that the "strategies that worked best at reducing partisan animosity essentially modeled good behavior, highlighting what Democrats and Republicans have in common as Americans or presenting people making a good-faith effort to understand someone with differing views."
But that will require elected officials on both sides of the aisle to set an example of leadership — something too many modern politicians have proven utterly incapable of doing in recent decades. That leaves it up to American voters who are sick of extremists driving the agenda.