IN ALL FAIRNESS, HE MAY JUST BE MENTALLY ILL:

It was a mid-December morning in 2007 -- the start of an interrogation unlike anything else in the public record of Trump's life.

Trump had brought it on himself. He had sued a reporter, accusing him of being reckless and dishonest in a book that raised questions about Trump's net worth. The reporter's attorneys turned the tables and brought Trump in for a deposition.

For two straight days, they asked Trump question after question that touched on the same theme: Trump's honesty.

The lawyers confronted the mogul with his past statements -- and with his company's internal documents, which often showed those statements had been incorrect or invented. The lawyers were relentless. Trump, the bigger-than-life mogul, was vulnerable -- cornered, out-prepared and under oath.

Thirty times, they caught him.

Trump had misstated sales at his condo buildings. Inflated the price of membership at one of his golf clubs. Overstated the depth of his past debts and the number of his employees.

That deposition -- 170 transcribed pages -- offers extraordinary insights into Trump's relationship with the truth. Trump's falsehoods were unstrategic -- needless, highly specific, easy to disprove. [...]

Trump has had a habit of telling demonstrable untruths during his presidential campaign. The Washington Post's Fact Checker has awarded him four Pinocchios -- the maximum a statement can receive -- 39 times since he announced his bid last summer. In many cases, his statements echo those in the 2007 deposition: They are specific, checkable -- and wrong.

Trump said he opposed the Iraq War at the start. He didn't. He said he'd never mocked a disabled New York Times reporter. He had. Trump also said the National Football League had sent him a letter, objecting to a presidential debate that was scheduled for the same time as a football game. It hadn't.

Last week, Trump claimed that he had seen footage -- taken at a top-secret location and released by the Iranian government -- showing a plane unloading a large amount of cash to Iran from the U.S. government. He hadn't. Trump later conceded he'd been mistaken -- he'd seen TV news video that showed a plane during a prisoner release.

But, even under the spotlight of this campaign, Trump has never had an experience quite like this deposition on Dec. 19 and 20, 2007.

He was trapped in a room -- with his own prior statements and three high-powered lawyers.

"A very clear and visible side effect of my lawyers' questioning of Trump is that he [was revealed as] a routine and habitual fabulist," said Timothy L. O'Brien, the author Trump had sued.

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