A wounded bear is a dangerous thing. Detested and defeated, Donald Trump is now in a tear-the-country-down rage. Day after day, he rips at the last remaining threads of decency holding this nation together. His opponent is the devil, he says — hate her with all your heart. Forget about the rule of law. Lock her up!

He’s made America vile. He’s got angel-voiced children yelling “bitch” and flipping the bird at rallies. He’s got young athletes chanting “build a wall” at Latino kids on the other side. He’s made it O.K. to bully and fat-shame. He’s normalized perversion, bragging about how an aging man with his sense of entitlement can walk in on naked women.

Here’s his lesson for young minds: If you’re rich and boorish enough, you can get away with anything. Get away with sexual assault. Get away with not paying taxes. Get away with never telling the truth. Get away flirting with treason. Get away with stiffing people who work for you, while you take yours. Get away with mocking the disabled, veterans and families of war heroes.

You know this by now — all the sordid details. For much of the last year, the Republican presidential nominee has been a freak show, an oh-my-God spectacle. He opens his mouth, our cellphones blow up. But now, in the final days of a horrid campaign, an unshackled Trump is more national threat than punch line. He’s determined to cause lasting damage.

Donald Trump is a political brawler. He is also a raconteur, a self-styled maverick, a political “outsider,” an adult male adolescent and the drunk guy at the local bar who picks fights with strangers by yelling racial and ethnic slurs or harassing women.

As I watched Hillary Clinton pummel Donald Trump during Monday’s debate, it occurred to me that beyond being merely unprepared to be president of the United States — see also Libertarian presidential candidate Gary Johnson and his inability to answer basic questions about international politics — that Trump is, in fact, supremely confident in his ignorance and sense of intellectual superiority over other people.

This is the psychological concept known as the “Dunning-Kruger” effect — put very simply, when stupid people don’t know that they are stupid — in action.

A democracy does not need to elect a person who fits the mold of Plato’s philosopher king in order to be healthy and successful. For example, the United States has had presidents who were intemperate (Lyndon Johnson), lacked preparation (Ronald Reagan) and overwhelmed by the demands of the office (George W. Bush). But Trump is something different. He is a fascist who wallows in his ignorance and stupidity about public affairs and then willfully confuses such attributes with wisdom and intellectual acumen.

Oct. 07 -- Donald Trump doesn't aim his nasty, middle-of-the-night tweets just at beauty queens he thinks have gained too much weight. He also targets architecture critics, me included, who've gotten under his prosciutto-thin skin. At 3:12 a.m. on June 22, 2014 , Trump directed his wrath at two of us: "I loved the day Paul Goldberger got fired (or left) as New York Times architecture critic and has since faded into irrelevance," he wrote. " Kamin next!"

The tweet came amid the war of words that ensued after I zinged Trump for the humongous, hideous sign he'd stuck on his mostly handsome Chicago skyscraper. I bring up the tweet ahead of Sunday's second presidential debate because Trump's character and temperament have become major issues in the campaign, and I can speak to both based on more than a decade of experience.

Over the years, Trump has courted me, comforted me, criticized me and sent me a handful of sometimes-fawning letters and notes. I saved the correspondence. Wouldn't you? It's fun to run your fingers over gold, raised-print letters that say "TRUMP." And the missives are telling. Combined with other things he's said and written, they show that Candidate Trump isn't all that different from Developer Trump. He remains a master media manipulator who can be charming, mercurial and vengeful. Only now he wants to be the most powerful man on earth.

THE CLINTON campaign has refused to deny or confirm the authenticity of a WikiLeaks report including apparent purloined emailed excerpts of her paid speeches to corporate audiences in the years between her departure from the State Department in 2013 and her declaration for president in 2015. We hope the excerpts are genuine, because at least in the texts made public as of Monday, the Hillary Clinton that emerges is a knowledgeable, balanced political veteran with sound policy instincts and a mature sense of how to sustain a decent, stable democracy.

This whole episode illustrates that point. Ms. Clinton kept the speeches under wraps out of fear that they would be distorted for political purposes by her populist foes. Alas, that fear was amply justified in this populistic, polarized environment, as the manufactured uproar over their release proves. The fact that Ms. Clinton’s eminently reasonable and open-minded words regarding the issues and her opponents are being treated as scandalous is the real scandal.

GOP tumbles toward anarchy as Ryan snubs Trump
‘It’s every person for himself or herself,’ former senator says

Trump’s truest believers start to worry: ‘You could easily lose this election’

House Democrats believe Trump troubles give them real shot at retaking majority

Donald Trump tried to call out Warren Buffett. He probably didn’t expect this response.

Republicans deserve their sad fate

The irony of ironies: Trump destroys the brand

Trump files for moral bankruptcy

Trump can’t stop his campaign’s death spiral

Donald Trump, Putin’s puppet

Donald Trump unleashes a stream of falsehoods

Reasonable Republicans can’t save the GOP from Trump
They're the ones who created him in the first place.