In preparing for her first major debate with Donald Trump, Hillary Clinton’s campaign readied her for two distinct opponents: The disciplined, “presidential” Trump who recently has been staying on message and gaining in the polls, and the mendacious, shoot-from-the-lip bully Trump, who has a 60 percent negative approval rating yet dominated the Republican primary race.

During the NBC Debate began on Monday night, Presidential Trump took the stage, using Clinton’s honorific title (“Secretary Clinton — yes, is that OK?” he asked. “Good. I want you to be very happy. It’s very important to me”), but only at first. About 15 minutes later, the shoot-from-the-lip candidate version appeared at the Trump’s lectern, and stayed on stage.

Despite facing his opponent for the first time in a one-on-one debate, Trump repeatedly interrupted Clinton during her responses, browbeat her on trade and foreign policy issues and blamed her and President Barack Obama for creating a nation on the brink of ruin.

But he also rejected concrete facts, declaring that the moderator, NBC News anchor Lester Holt, was incorrect for mentioning Trump was in favor of the 2003 U.S. invasion of Iraq and that Trump perpetuated the falsehood that Obama isn’t an American citizen, two claims that have been widely proven. Trump mugged, sighed, fidgeted and, leaning into the podium microphone, said, “No!” or “Wrong!” when Clinton or Holt brought up his past statements.

The GOP candidate seemed driven to defend himself against even the smallest slight. He complained about Clinton’s “not nice” political ads against him. He bristled when she suggested his as-yet-unreleased taxes would show he’s not as wealthy as he claims. He pushed back and questioned her “stamina” when she suggested he’s unfit to be commander-in-chief — even as his free-form answers over the last half of the debate often trailed into contradictions and bordered on incoherence.

“Well, I have much better judgment than [Clinton] does,” he bragged, pointing to his supposed opposition to the Iraq war. “There’s no question about that. I also have a much better temperament than she has, you know? I have a much better — she spent — let me tell you — she spent hundreds of millions of dollars on an advertising — you know, they get Madison Avenue into a room, they put names — oh, temperament, let’s go after — I think my strongest asset, maybe by far, is my temperament. I have a winning temperament. I know how to win.”

In other words, it was vintage Trump, deploying the same dystopian vision, brash attitude and loosely held command of the facts that fired the imagination of white working-class Republicans, and helped Trump blast his way through a 16-candidate GOP primary field to win the nomination.

Though the performance likely didn’t hurt him with his core supporters, it may have sowed doubt in the minds of undecided or swing voters — the 10- to 15-percent share of the electorate on whom the election will likely turn.

In each of the three topics — restoring prosperity, the direction of the nation, and national security — Trump played the role of strong leader, delivering a forceful, if at times vague, answer related to the topic, then pivoting to his core message: America is in decline, and only his business savvy and populist agenda can reverse it.

[RECAP: Trump, Clinton Spar in First Presidential Debate]

Debating a point about climate change and green energy, Trump rejected his own past statements suggesting climate change is a hoax (“I never said that”) and turned it into a critique of federal spending (“Our country is losing so much in terms of energy, in terms of paying off our debt. You can’t do what you’re looking to do with $20 trillion in debt”). He then portrayed Clinton as a career politician, a member of the political elite that his base loathes.

“And, Hillary, I’d just ask you this. You’ve been doing this for 30 years,” he said. “Why are you just thinking about these solutions right now? For 30 years, you’ve been doing it, and now you’re just starting to think of solutions.”

After the two clashed on taxing the wealthy and Trump’s unclear proposal to pay for tax cuts by repatriating offshore corporate profits (“Please — fact checkers,” Clinton mocked. “Get to work”) Trump suggested the new revenue would rebuild urban neighborhoods left to decay under President Barack Obama and Clinton. The former secretary of state looked bemused.

“I have a feeling that by, the end of this evening,” she quipped, “I’m going to be blamed for everything that’s ever happened.”

“Why not?” Trump retorted.

Yet Trump left himself open to barbs from Clinton — her quip about the U.S. being a debtor nation because Trump hadn’t paid income taxes in many years drew applause from an audience that had been admonished to stay quiet. He didn’t effectively rebut her portrayal of him as deadbeat millionaire who stiffs his creditors, a thin-skinned political novice and a defense-policy know-nothing who gives U.S. allies heartburn.

He stumbled when Holt pressed him about his role in perpetuating questions over Obama’s birth, repeating the false claim that Clinton started the controversy but he ended it, and refusing to say why he kept the rumor going five years after Obama produced his official birth certificate from Hawaii.

When the topic turned to foreign affairs, Trump again repeated his plan to revisit U.S. defense treaties, including the one-for-all alliance with NATO member states. But his answer, long on platitudes but short on specifics, seemed to indicate a lack of perparation for arguably his biggest moment in the campaign so far.

“The single greatest problem the world has is nuclear armament, nuclear weapons, not global warming, like you think and your — your president thinks,” Trump said, perhaps not recalling that Obama won the 2009 Nobel peace prize for his work on nuclear disarmament.

Ultimately, Trump’s ragged performance probably won’t torpedo his poll numbers, at least not immediately. Fueled almost solely by the distress of the white working class, his campaign has survived bogus claims, inconsistent positions, unclear policy proposals and outright mockery — problems that would have crippled or killed an ordinary presidential candidate.

Unless Trump reverses course, however, and musters the kind of focus and discipline required to stand up to Clinton on a debate stage, he won’t be able to win moderate voters who are only beginning to pay attention to this marathon of a campaign — voters who might be willing to give Presidential Trump a look, but would agree with Clinton that the version of Trump who appeared Tuesday night shouldn’t come anywhere close to the Oval Office.

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Donald Trump’s Woeful Debate Performance Won’t Deter His Die-Hard Fans originally appeared on usnews.com