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President Trump surprised the White House press corps and the still surprisable world when he gave an impromptu press Q&A on Wednesday night, appearing in Chief of Staff John Kelly's office and saying he "would love to" testify for special counsel Robert Mueller and would do it under oath.

 

What could go wrong?

 

"Speaking from experience, I think the president's attorneys should grab their worry beads," says author Tim O'Brien, who was sued for libel by Trump for his 2006 biography "TrumpNation."

 

In the suit, Trump claimed that O'Brien had misrepresented his business record and underestimated his wealth. Trump ultimately lost, but not before giving a two-day deposition that portends what Mueller, his team and the nation are in for, says O'Brien. It didn't go well for the future president," he writes in BloombergView. Interrogated by lawyers who had done their homework, "Trump ultimately had to admit 30 times that he had lied over the years about all sorts of stuff: how much of a big Manhattan real estate project he owned; the price of one of his golf club memberships; the size of the Trump Organization; his wealth; his speaking fees; how many condos he had sold; his debts, and whether he borrowed money from his family to avoid going personally bankrupt. He also lied during the deposition about his business dealings with career criminals." Lawyers also had to explain to Trump the difference between an exaggeration and a lie. 

 

Overall, O'Brien said that Trump seemed ill-prepared for attorneys' questions, which aligns with reports that the president shies from reading briefing books to prepare for the decisions before him. He was "proud" of a document that summarized his business holdings, but seemed surprised when it was pointed out in court that it wasn't a reliable report of his wealth. This opens the door for Mueller and his team to surprise Trump with conflicting statements he's made both in the public record and in confidential materials.

 

And Trump's biggest weakness might be his insistence that he knows everything, says O'Brien. "He basks in the perception that he’s the man in charge and everyone else follows his orders," he writes. "Trump couldn’t resist saying that his minions at the Trump Organization and elsewhere were just following his orders, a boast that also raised the legal stakes for himself (even if he didn’t realize that’s what he was doing)."