Unless Trump is talking to someone who buys into his loopy conspiracies and will avoid pointing out that his answers are incoherent, he might be embarrassed, humiliated even, which for a raging narcissist like Trump is worse than anything.
When a prepared, sober newsperson asks Trump why he still doubts that Russia was solely responsible for meddling in our election or why Trump still buys into the Russian propaganda that Fiona Hill warned us to avoid, he will have a choice: Stick to the base’s Earth 2 version of events (and be exposed as a crackpot), or disavow crazy-talk and face the wrath of his base. Trump’s reliance on conspiracies “works” only so long as everyone plays along. As soon as someone responds “Whaaaat?,” the jig is up.
We saw a version of this in the impeachment hearings, when Republican congressmen tried to ask Hill, Army Lt. Col. Alexander Vindman or William B. Taylor Jr. about some aspects of the Infowars nuttery. They received blank stares in response. You cannot ask insane questions of those who don’t inhabit your parallel universe and expect not to be exposed as a crackpot.
Trump has other reasons to fear the debates, of course. In 2016, Trump, by any measure, lost all three debates to Hillary Clinton. (“In the 2016 general election debates, Mr. Trump repeatedly complained about being at a disadvantage to Hillary Clinton. . . . And the post-debate polls showed Mr. Trump had good reason to be concerned: Mr. Trump and Ms. Clinton were essentially tied in the polls going into the first debate, but she received a bump after each of the three face-to-face matchups.”) The Democratic contenders for 2020 are all more articulate and verbally nimble than Trump, able to skewer him for spouting nonsense and to point out that his answers are not answers at all.
Worse, his opponent or the audience might laugh at him, as did world leaders recently or the United Nations delegates in 2018. The Post reported on the latter: “The embarrassing exchange came when Trump boasted that his administration had accomplished more over two years than ‘almost any administration’ in American history, eliciting audible guffaws in the cavernous chamber hall.” Outside his bubble of sycophants he is vulnerable. “At the United Nations, Trump’s claim to have done more in less than two years than most of the 44 previous administrations defied any bounds of reality — or hubris. The difference was that he was not talking to a room full of excited, red-hat-wearing ‘MAGA’ supporters who cheer him on.”
The thought of facing real-world opponents and real-world journalists must be panic-inducing for Trump. Receiving boos at a World Series game or UFC event, where he can pretend not to hear and need not respond, is one thing. But being put on the spot, laughed at or booed (all distinct possibilities at a debate) with no place to run and hide must petrify him.