An attitudinal pandemic is poisoning the American body politic to the worst extent of our lifetimes.

The disease manifests itself in a widespread, unreasoning refusal by people on all sides even to consider that their chosen team or champion can possibly be wrong or that the opposing side might have a point, no matter what the facts are. This isn’t just ordinary “ confirmation bias ,” which is a largely subconscious tendency to interpret evidence so that it favors one’s already desired conclusion. Instead, this seems to be an extreme variant of confirmation bias that amounts to flagrant dishonesty, obduracy, or lunacy. Or a combination thereof.

What it is is a willfully alternative reality, spreading throughout American politics like the plague, exacerbated by a population now so poorly educated that large swaths of it have no idea how logic works or how to distinguish fact from fevered fabrication. It was evident Wednesday from both Republican and Democratic members of a July 12 House Judiciary Committee hearing with FBI Director Christopher Wray, himself a greased-eel character slithering away from responsibility for copious sins of his bureau (about which I’ve written numerous times , but that’s a different subject).

The deplorable details of the hearing were just a symptom, not the disease, and thus bear no specific recounting here. More broadly, as mere examples of the large contagion, consider some things that adherents of one side or the other absolutely refuse to admit about Presidents Donald Trump and Joe Biden.

Team Trump will not acknowledge anything wrong with his behavior or his performance aside from, well, “mean tweets,” even though if someone on the other side had done the same things, Team Trump would demand scalps. Tens of millions of Trump supporters deny there’s anything wrong with him willfully, deliberately refusing to comply with the Presidential Records Act or refusing to comply with laws governing classified material. They deny it was frightfully wrong to keep documents containing top nuclear secrets and potential war plans in the unsecured bathroom of a resort already known for being breached by foreign agents.

They likewise deny it was wrong to ignore 63 different court rulings saying he had indeed lost the 2020 election, wrong to assemble a mob and feed them lies about the election, wrong to urge the mob, some of whom he knew were armed, to march on the Capitol, and wrong to keep spewing invective at his own vice president even after he knew some mob elements were demanding the vice president’s execution.

They deny he was wrong to defy a law he himself signed that required provision of arms to Ukraine, wrong to demand that a foreign government gin up a case against his political opponents that his own Justice Department told him was nonexistent.

On job performance, they insist he enjoyed massive success against illegal immigration even though illegal immigrant encounters were more numerous during Trump’s one term than they were during either of Barack Obama’s two terms and even though he shut down the government for five weeks to demand more border wall funding, only abjectly to capitulate by securing less wall funding than his opponents originally offered. Team Trump also excuses him being the biggest spender and biggest government debt creator (World War II excluded) in U.S. history. And on and on, and on.

Team Biden and his liberal media enablers, sycophants, and apologists, meanwhile, go to absurd lengths to hide his many decades of outlandish lies, to excuse or look away from his family’s obvious corruption, and to ignore what by now is massive, compelling evidence suggesting he know about and benefited from that corruption. Or that his minions in the DOJ and FBI took extraordinary steps to bury that evidence.

A family doesn’t set up more than a dozen shell corporations through which $10 million in foreign money is funneled to sons, daughters-in-law, and nieces, all while foreign and domestic “business associates” just happen to meet repeatedly with the vice president or his staff at just the times when the vice president is directly overseeing diplomacy affecting those foreign entities, without there being intensely unethical influence-peddling going on.

And so on, and on. Also so on with myriad other examples not involving Trump or Biden, but where one side or the other says facts aren’t facts and that the same thing they excuse for their own side would be downright evil if done by their opponents.

On July 12, the Washington Examiner featured an essay by one Julian Adorney lamenting today’s record levels of “affective polarization,” which is “the gap between individuals’ positive feelings toward their own political party and negative feelings toward the opposing party.” Adorney’s diagnosis is correct. If the disease gets any worse, it could kill the American republic.