Fox News host Howard Kurtz is known for defending Trump from critical voices in the media — which is exactly why his new book describing the chaotic Trump White House is so damning.

In the instant bestseller “Fire and Fury,” author Michael Wolff gave a scathing account of the unprecedented chaos inside the Trump White House, prompting a wave of frenzied media debate and howls of outrage from Trump’s supporters. Trump feared the book so much that he actually threatened a frivolous lawsuit against the publisher.

But as the Washington Post argues, an upcoming book by Fox News host Howard Kurtz could cause bigger problems for Trump than anything Wolff wrote.

Kurtz is very favorable to Trump in general, often defending him from more critical voices in the media. After it was revealed that Trump rejected a deal on immigrant children for fear too many people would come in from “shithole countries,” Kurtz defended him, insisting the racism would have been totally fine if not for the profanity.

And yet in his new book, “Media Madness: Donald Trump, the Press, and the War Over the Truth,” Kurtz’s account essentially agrees with Wolff on the broader point: Trump’s White House is in chaos, and even his own advisers have been taken aback by his poor and capricious judgment.

As the Post’s Aaron Blake notes, one of the most astonishing facets of Trump’s behavior is that he “has a tendency to do whatever his advisers most strongly advise him against.”

For example, Trump was reportedly “strongly advised” not to send then-press secretary Sean Spicer out in front of the cameras to argue with reporters about his inaugural crowd size. But he did it anyway — and later admitted, “I shouldn’t have done that.”

Much to the horror of then-Chief of Staff Reince Priebus, Trump sent a tweet in August announcing his decision to ban transgender people from the military — a move that apparently came “out of nowhere” and completely blindsided his aides.

“Oh my God, he just tweeted this,” Priebus reportedly said at the time, according to the Post.

His advisers even have a name for that behavior, Blake notes. They call it “defiance disorder.”

Trump has long shown that he is automatically against anything for which President Barack Obama advocated. But the fact that he is also compulsively in favor of what his advisers tell him he should not do is truly disturbing. He is essentially governing as a spiteful toddler — something that even his own chief of staff has confirmed.

If Trump’s “defiance disorder” has shaped so much of his presidency, it bodes poorly for his ongoing capacity to make decisions or negotiations on anything — and even a Trump-friendly Fox host can see that.