There are two questions any definitive account of George W. Bush's presidency must answer. One has dogged him from the very start of his presidential campaign in 1999: Is he as stupid as he seems? The other has dogged him for the last five years: Why did he decide to invade Iraq?

The first question about Bush's intelligence is relatively easy to dodge but exceptionally hard to answer. No, he's not stupid, but he is simplistic and sometimes sloppy. He has a sharp strategic mind when it comes to politics, and he can delve into policy details when he wants to. However, everyone who knows the president realizes that is only a partial answer. The deeper question boils down to this: How does he apply his intelligence? Why does he disdain the policy experts and the nuance in favor of his gut judgment?

The answer to this question might ultimately help Bush historians with the other challenge -- how to understand the abrupt shift from the war against al-Qaeda to the singular focus on Saddam Hussein and Iraq. At this late stage of his presidency, there really isn't much point in writing a book about Bush without grappling with these huge, unanswered questions. This is a daunting prospect for any biographer, and Bush himself is not exactly helpful here. He hates this kind of psychobabble, and his most loyal aides and friends do, too. At his getting-to-know-you lunch with author Robert Draper, the president declined to gaze into his own navel. "You're the observer," he said, "I'm not. I really do not feel comfortable in the role of analyzing myself." This is the kind of sly putdown that Bush performs effortlessly. After six sit-down interviews with Draper, Bush seems to have revealed little about the inner workings of his mind.

Draper emerges with a treasure trove of detail and anecdotes, but he often doesn't delve -- or isn't allowed to delve -- into the deeper questions. Early in his book Dead Certain, he tells the story of Bush's failed bid for Congress in 1978. Against all the best advice, Bush decided to run against a conservative West Texas Democrat, Kent Hance. He lost badly, but not embarrassingly. Explaining his decision to Draper, he said, "You can't learn lessons by reading. Or at least I couldn't. I learned by doing. I knew it was an uphill struggle. But see, I've never had a fear of losing. I didn't like to lose. But having parents who give you unconditional love, I think it means I had the peace of mind to know that even with failure, there was love."

Let 1,000 PhDs bloom. Here is a president who boasts of reading around 100 books a year, promotes reading standards and No Child Left Behind, graduated from Yale and Harvard, and is married to a librarian. Yet he thinks he can't learn lessons by reading. You can almost hear the critics scoff. Given his current situation, if the president had spent more time studying Iraq and less time doing Iraq, he might have emerged with a different conclusion about military action.

And what about that lack of fear, that nonchalance about failure? This might just explain the deep trust in his own snap judgments. But why the immediate connection to his parents' love? Are his relationships with his parents and siblings really so simple?

Sadly, you won't find the answers to those questions in Dead Certain. But there are plenty of eye-popping moments that Draper has uncovered, to his huge credit. It's not coincidental that the anecdote above comes from a race in Texas and is sourced to a pre-presidency interview in 1998. Draper is far more enlightening about these Texas moments than the Washington years.

For instance, he vividly trashes Bush's much-vaunted business experience as general manager of the Texas Rangers baseball team. He describes his groupie behavior with the team, painting a memorable picture of what he mockingly calls the First Fan and the Jocksniffer-in-Chief. But Draper spends just one paragraph on Bush's decision to give up alcohol, and even less space on his rigorous exercise regime. These are two pillars of the president's life and character.

He uncovers great anecdotes about Bush's love of punctuality (the president locked Colin Powell out of a Cabinet meeting for being late). He tells a wonderful story about Bush's new wardrobe, and his sartorial transformation from slob to governor (including his former love of beltless polyester slacks). Yet Draper doesn't try to reconcile the self-discipline with the slobbishness, even as he watches Bush stuff a hotdog into his mouth.

Dead Certain features a compelling account of the 2000 South Carolina primary and the destruction of the McCain campaign. Yet it reveals far less about the cold-blooded calculation inside the White House to exploit 9/11 and Iraq for campaign purposes in 2002 and 2004. Bush's disputed victory in 2000 and the impact on his presidency: half a page. The challenge of electricity generation in occupied Iraq: an entire chapter.

As for the most opaque relationship inside the White House -- the mystery of the Bush-Cheney axis -- the book is mostly silent. We learn that Karl Rove opposed Cheney as the VP pick because choosing one of Bush 41's Cabinet members would appear "needy" and off-message about the candidate's independence from his father. Then nothing more -- not the fateful discussions about Iraq nor the emotional talk about Cheney's hunting accident.

Here we have the story of a needy candidate who turns into a swaggering war president. Can one person be both needy and confident? Yes, if you're President George W. Bush. If only we knew why.

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