Literally understood, the United States does not have tribes. Virtually every U.S. citizen is an individual who is descended from an immigrant. Enjoying neither a shared ethnicity nor a state religion, we rely on shared beliefs for our cohesiveness as a nation.

Over time this cohesion has served us well. Unfortunately, it is now in freefall.

The only two U.S. political parties big enough to matter are the Democrats and Republicans. In 2016, a lot of them did not trust each other. Thirty-five percent of Democrats thought Republicans were immoral, and 47% of Republicans returned the favor. Today, it is even worse. Sixty-three percent of Democrats and 72% of Republicans believe the other is more dishonest than other Americans, according to a poll cited on PBS NewsHour.

In a heterogeneous society of 330 million people, one would expect divergent and, at times, antagonistic views on any number of issues. And that expectation has been realized. The country is divided on abortion. It was divided on Vietnam.

Going further back, we were divided on school integration (busing minority children into largely white schools) and affirmative action (favoring minorities in government hiring and contracting). Further back still, we were divided over whether to enter World War II (most Americans were opposed) until the Japanese attack at Pearl Harbor.

Why are we so divided now?

The answer is as multifaceted and complex as the human condition, and very likely includes a steepening (and some would argue, staggering) level of income inequality for most Americans, coupled with rapid changes in how many of us now work (remotely) and live (in internet/social media echo chambers).

Less acknowledged is what may be the most important reason of all. Which is that the current divide is not about policy – however important. Instead, it is about who and what we are as individuals and people.

On the Republican right, candidates routinely run on the lie that our elections are being "stolen." Media personalities attract millions of viewers by parroting untruths about weaponizing law enforcement to pursue political agendas and mischaracterizing repeated efforts to police a runaway former president's flouting of the law as a "witch hunt." Climate change is dismissed as a canard. Vaccines are contorted into a conspiracy.

Opponents are described as traitors.

On the Democratic left, progressive politicians and media pundits routinely share their opinions as received truths. Only "haters" question the "obvious truth" that judges and prosecutors are so racist that none can be trusted to set bail for defendants lawfully arrested. Those who doubt whether allowing adolescents to proclaim their gender fluidity makes sense or believe we need to control our national borders are engaging in "hate speech." Since minority students are under-represented in honors classes, the answer is to end honors classes. And more broadly, it is not enough to tolerate others; you must embrace them - even if you are poor, white, uneducated, can't pay your bills, and don't know anyone who is Black – you must advocate for Black Lives Matter, or you are a "hater."

Both of these extremes are untethered to facts and common sense. Both are outside most Americans' lived experience. Both represent the views of minorities in each respective party. And both have crowded out other views from the arena of public perception. Because most of us don't feel angry enough, qualified enough, or have the opportunity to do things like give speeches, write columns, and pontificate on the airwaves. Those who do are heard. The rest of us are not. Leaving many (indeed, most) of us perplexed, silent, and alienated.

There is an answer, but it won't come easy.

It involves doing the thing that human beings across the globe do far too infrequently and rarely do well. That is, to stop. Look in the mirrors of our own lives. Reflect on what we have experienced, try to make sense of it, and use that understanding as a prism to view the wider world and assess the pundits who make a living (or seek power) distorting it. Appreciate what has been accomplished and assess where we have fallen short. Recognize that almost all of us share certain basic priorities. Nearly all of us will help a neighbor – whether we like him or not - if his house is on fire. For most of this country's history, many flaws were glossed over, and others minimized.

But an overarching idea – of the U.S. as a huge step forward in humankind's progress towards individual freedom – was and remains valid.

Paul wrote to the Corinthians that "[w]hen I was a child, I spoke as a child. I understood as a child, I thought as a child: when I became a man, I put away childish things."

Americans don't need to be wise to begin closing the divide. But they do need to meet one fundamental responsibility.

They need to grow up.

Andrew Leven is a former federal prosecutor, columnist, and attorney with the US-based law firm of Dilworth Paxson.