WASHINGTON — The outcome of the 2016 presidential election reinforced a certain lesson. No, not that the universe is a cold, empty, meaningless void, and that hope and justice are pretty lies told by self-deceived fools.

I mean the other lesson: Don’t underestimate Donald Trump.

All good lessons, however, are eventually overlearned, especially by once-burned political commentators. In this case, our reticence disguises just how weak Trump really is. While it is absurd at this point to predict anything about the 2020 presidential election, no sane candidate would prefer to be playing Trump’s hand.

The most recent national election — the 2018 midterms — showed strong Democratic enthusiasm and collapsing Republican support in many suburban areas. Take Northern Virginia’s 10th Congressional District, which Republican Barbara Comstock won in 2016 by nearly 6 percentage points. In 2018, Comstock lost her seat to a Democrat by 12 points — a massive swing during the first two years of the Trump presidency. Trump placed the blame on Comstock— who had sided with Trump 98% of the time in House votes — for being insufficiently enthusiastic about his person. It was a remarkable display of gracelessness and delusion.

The question arises: What has Trump done in the interval between the midterms and today to change the minds of suburban voters who helped win the House for Democrats in Virginia’s 10th District and elsewhere? The answer occurs: nothing. Nothing at all.

Trump’s current poll numbers are poor — in some cases historically poor. Unlike every other recent president, he has never reached a job approval rating of 50% according to Gallup. A recent Quinnipiac poll puts his approval at 38%. A recent poll in Virginia by Roanoke College had Trump’s job approval at 27% — an 11-point drop since February.

There is evidence that his signature political approach — his mix of rancor and racism — is alienating women in large numbers. Overall, Trump won white women by 2 points in 2016. Recent polls have him losing all women by double digits in matchup polls against all the main Democratic contenders. According to 2016 exit polls, Trump won white, working-class women by 27 points. Two recent polls have him up by only 7.

External conditions may be turning against Trump. There are signs of weaker economic growth, increasing fears of recession and an apparently endless trade war with China that (according to a recent economic analysis) will cost the average American family $460 over the course of a year. The Quinnipiac poll finds, for the first time, that more Americans think Trump is hurting the economy than helping it. He is already pre-blaming American companies and the Federal Reserve in case economic conditions turn south — indicating the shape of his worst fears.

And internally, the president’s precarious emotional balance seems further unbalanced by adversity. His normal chaos has become whirling, flailing, frothing chaos. He “hereby ordered” American companies to cease doing business in China — transcending the debate between conservative and progressive economics with a dose of fascist economics. He promised pardons to aides who broke the law in building the southern border wall. He used his high office to attack Omarosa Manigault and Debra Messing. He claimed “Fox isn’t working for us anymore!” (Truth rating: Pants on Fire!) He suggested one of his properties as the next location for the G-7 summit, then defended it against one visitor’s charges of bedbug infestation. He denied a well-reported news story revealing that he proposed to blow up hurricanes with nuclear weapons. And he tweeted out the almost-certainly classified photo of a failed Iranian missile launch. Says one strongly Republican friend: “I’m trying to imagine what would be happening on the right today if (Barack) Obama were president and had tweeted out a classified photo of an Iranian missile site clearly taken from his intelligence briefing with a stupid comment about it. People would be calling for his impeachment. And yet Trump does it and everyone has an excuse to offer.”

To win reelection, Trump will need to take and get credit for a strong economy, control his self-destructive tendencies on Twitter and in press availabilities, and draw a very liberal Democratic opponent. The first condition is very much up in the air. The third is in the hands of Democrats. Recent events, however, show that the second condition will almost certainly not be met. Trump seems incapable of carrying forward any political strategy that requires something more than immediate obedience to his rampant impulses.

Michael Gerson’s email address is michaelgerson@washpost.com.