It must be confusing to President Trump that the political system, the media and a majority of voters have suddenly called him on a deception, on a lie. It has seldom, if ever, happened before.

It did not seem to matter when he claimed to have evidence that President Barack Obama was born abroad; or when he insisted that crowds of American Muslims celebrated 9/11 in the streets; or when he said that the murder rate was the highest in half a century; or when he claimed the largest electoral-vote victory since President Ronald Reagan; or when he asserted that massive voter fraud cost him a popular-vote win; or when his press secretary claimed the largest inaugural crowd in history.

What about this particular accusation — that Obama ordered the bugging of Trump Tower — was finally too difficult for the body politic to swallow? How was this different from the maggoty meals that preceded it?

Some of the difference surely comes in having historically high and intense disapproval ratings. A president who is low in the polls is vulnerable to narratives of scandal and failure. Perhaps the authorities who refuted him brought greater gravity to the task. The FBI director and Congress still carry more weight than PolitiFact.

But whatever the reason, the reaction to Trump’s latest deception is a sign of civic health — though really more of a weak, irregular pulse.

(Monica Akhtar/The Washington Post)

Trump is an intuitive demagogue. He knows that by taking and holding the high ground of epistemology (how we know what we know), he can control the political landscape. So he dominates partisan media, attempts to discredit other sources of information (the media, the FBI, the CIA, the Congressional Budget Office) and builds a type of loyalty impervious to factual correction.

Trump did not create the conditions for his own rise. During the Obama era, conservative media, particularly talk radio, adopted what Vox’s David Roberts calls a “tribal epistemology.” All facts were filtered for the benefit of the tribe. In this approach, information is useful only as ammunition. And conflicting views are entirely the result of bad faith. This was a political wave well suited to an empty vessel. Trump was willing to say anything the medium demanded.

At the same time, a different tribe — academic liberalism — was moving in a similar direction. In this approach, the very possibility of truth is undermined by philosophies of relativism and reductionism. Conservatism is seen by them as a fight for privilege and oppression. Conflicting views are dismissed as a matter of bad faith. And dissenting voices in the academy can be silenced for the benefit of a rootless righteousness.

Put a representative of each of these tribes in a room — one in red war paint, the other in blue — and the result would be a shouting match, or worse. (I am actually describing many Americans’ table discussions last Thanksgiving.) On issues such as climate change or gun control, the reds and blues do not see different ways up the mountain. They see two different mountains — two different fact sets, two different political, social and scientific realities.

In an important way, the views of the right-wing populist tribe and the left-wing academic tribe are not symmetrical. Only one has seized control of a political party. And this makes the critique of Trumpism more urgent.

The main problem with tribal definitions of truth is that conflict can be expressed only in combat (verbal and otherwise). If rational arguments, conducted in good faith, holding out the possibility of compromise, are impossible, there is only one way to decide between conflicting views: power. If the enemy is beyond persuasion, all that remains is compulsion. This may be why so many of Trump’s attempts at persuasion have an air of threat and menace. “Oh, Mark,” Trump recently told Rep. Mark Meadows (R-N.C.) during a meeting of House Republicans, “I’m gonna come after you.”

A commitment to truth is not the only democratic value. It should be accompanied by an appropriate humility and respect for the dignity and rights of others. Both James Madison and Maximilien Robespierre pursued certain truths about human equality; only one employed the argument of the guillotine.

But there are times and places in which the truth needs bold defenders. Vaclav Havel stepped forward and refused to live “within a lie.” Said Alexander Solzhenitsyn: “In our country, the lie has become not just a moral category but a pillar of the state.”

That is a condition no democracy can accept and good reason to reject the lies that bind.

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