Never been wrong yet. Photo: Nicholas Kamm/AFP/Getty Images

One of President Trump’s most bedrock character traits is his refusal to truly reckon with any piece of information that reflects poorly on him. This self-aggrandizing, reality-denying flavor of egotism has defined Trump for decades, through his roller-coaster business career and into political life. In recent months, it has sometimes veered into the straight-up delusional, as when he reportedly claimed last year that it wasn’t actually his voice on the Access Hollywood tape.

Trump’s insistence that everything is going great was validated in unprecedented fashion when he won the presidency despite some of the strongest headwinds imaginable, shocking almost everyone — possibly including, on some deep level, himself.

But now, finally, the president’s unwavering confidence may finally be about to take a serious electoral toll.

The New York Times reported on Saturday that in the runup to the midterm elections this fall, President Trump is simply not listening to advisers and lawmakers who tell him what anyone can plainly see: Republicans are in deep trouble.

President Trump is privately rejecting the growing consensus among Republican leaders that they may lose the House and possibly the Senate in November, leaving party officials and the president’s advisers nervous that he does not grasp the gravity of the threat they face in the midterm elections.

Congressional and party leaders and even some Trump aides are concerned that the president’s boundless self-assurance about politics will cause him to ignore or undermine their midterm strategy. In battleground states like Arizona, Florida and Nevada, Mr. Trump’s proclivity to be a loose cannon could endanger the Republican incumbents and challengers who are already facing ferocious Democratic headwinds.

In election after election over the last year and a half, Democrats have vastly overperformed their expected vote share, largely thanks to animus toward the president. They have triumphed in a Pennsylvania Congressional district where Trump won by more than 20 points, picked up a Senate seat in ruby-red Alabama, dominated state races in Virginia, and made close several contests that almost certainly would have been Republican landslides in previous years. It’s true that Democratic polling on the generic ballot is not as overwhelming as it could be at this stage, but the bulk of evidence points to a very strong Democratic showing in November, and Republicans have been sounding the alarm for months.

Trump’s reaction to all this: everything will be just fine.

If Mr. McConnell’s warning was not clear enough, Marc Short, the White House’s legislative liaison, used the dinner to offer an even starker assessment. The G.O.P.’s House majority is all but doomed, he said.

But Mr. Trump was not moved. “That’s not going to happen,” he said at different points during the evening, shrugging off the grim prognoses, according to multiple officials briefed on the conversation.

The Times piece also reports that, as his fellow Republicans fret, Brad Parscale, the president’s pollster, is feeding him inaccurate, Trump-friendly poll numbers, which the president is more than happy to parade on Twitter.

Why does this matter? Most presidents, even if they claim not to be obsessed with polls the way Trump is, have a pretty good idea of their own political currency, and adjust their alignment with their parties accordingly. Sometimes, presidents realize that they are not welcome by members of their own party in certain areas; for example, a then-struggling Barack Obama avoided red states in 2014, and George W. Bush was not always welcomed with open arms on the stump, even in Republican-friendly districts, circa 2006.

Something different is going on this time around. President Trump remains enormously popular within the Republican Party; most Republican members of Congress have made the calculation that even if Trump is underwater in their state, defying the president would be a political loser, since it leave them without any reliable constituency.

The problem is not only that Trump refuses to believe that Republicans will lose, but that, even if he were sufficiently worried, he doesn’t care enough about his own party to bother helping. He is connected enough to the GOP that he sees it as an extension of his own electoral prowess, but not so connected that he will muster the focus and energy needed to boost candidates who aren’t him. (Granted, this may be impossible for him on a cellular level.)

Establishment Republicans reportedly want Trump to flog the GOP’s unpopular tax law on the campaign trail. The president is pushing back on this directive — which he is right to do, since the unpopular law probably isn’t galvanizing anyone to vote.

But the president’s own, predictably unpredictable routine is unlikely to work much better. He might attack vulnerable Republican Senators he disagrees with; he might serve more as a distraction than a cheerleader, the way he did when he suddenly started complaining about Colin Kaepernick at a campaign rally for Luther Strange in Alabama; he might just ramble about himself. In other words, he’ll put on the Trump show, which is the only thing he knows how to do.

This routine won’t turn off voters who already love the president. But it’s more likely to spark another Trump news cycle than rally much-needed enthusiasm for Republican candidates.

Sometimes, Republicans will get lucky when Trump stumbles upon a personal grievance, as he has with vulnerable Montana Senator Jon Tester, whom he blames for scuttling the Ronny Jackson Veteran Affairs appointment. The GOP’s best hope may be to invent reasons that red-state Democrats are hurting Trump personally, then watch him go wild on Twitter and the campaign trail.

Republicans seem to have grasped the lesson that Trump needs to be personally invested in their election results. They are trying to make the stakes of the election startlingly personal, reportedly telling Trump that if he doesn’t help them out this fall, they may not have his back if and when Democrats initiate impeachment proceedings next year. That stark warning may perk Trump’s ears up, but it’s just as likely to be perceived as an unacceptable intramural threat, not as motivation to work for the party.

However Trump performs on the campaign trail, and however Republicans fare this fall, the president will continue living in a bubble of his own making. Because Trump was right to dismiss the concerns of the many, many people who insisted he couldn’t win in 2016, he can now perennially point to that shocking election result as proof that his instincts, not some politico egghead’s, are always correct. And if Republicans lose big this year, he’ll just say they didn’t stick by him closely enough.

It’s a dishonest, solipsitic approach to life. But it’s one that has worked shockingly well for Donald Trump.