You’ll notice that none of these nuggets gets us into the psyche of the Stranger in Chief. Mr. Todd does offer up some tantalizing thoughts on the subject. He tells us that Mr. Obama’s former colleagues in the Senate believe that things had always come too easily for the one-term Illinois senator—and that for this reason they prefer to deal with Vice President Joe Biden , a war-scarred politico who can “actually understand their frustrations.” (The most revealing passages in “The Stranger” concern Mr. Obama’s more transparent vice president, whose affability is so reflexive that when the White House patched him into the phone of a different senator than the one he intended to speak with, he simply made a new friend. Mr. Biden, Mr. Todd reports, finds his boss to be thin-skinned.) On the House side, the author observes that Mr. Obama’s relationship with former House Speaker Nancy Pelosi suffered because he “had few ties to Pelosi”—which of course raises the question: Then why didn’t the nation’s top Democrat set out to develop some ties? Mr. Todd says that it has been easier for Mr. Obama to be “playing hardball with members of his own party” than with Republicans and that “nothing irks Mr. Obama more than the idea that he’s somehow a leftist or liberal; he believes that most of his ideas are old Republican ideas from another era.” Yet none of this is thoroughly explored in the book, and what we’re left with is an amorphous composite sketch of an undefined subject.

Mr. Todd has been busily demystifying election cycles at NBC, and in places “The Stranger” reads as if it were written in haste. Phrases like “a tad” and “thick as thieves” are repeated on the same page; inside-baseball knowledge on the part of the reader is often assumed. Jim Messina, the White House deputy chief of staff, emerges out of nowhere as Mr. Obama’s “point man” on the “Don’t Ask, Don’t Tell” repeal without any elucidation of Mr. Messina’s crucial role in the administration or how he got to the White House to begin with. Similarly, a set piece on gay former Republican operative Ken Mehlman ’s role in the same legislative effort fails to mention that Mr. Mehlman had been George W. Bush’s political director when Mr. Bush came out in favor of a constitutional amendment to ban gay marriage. Reference is made to “the Tea Party politics of the Obama era” without explaining to the reader what the Tea Party is or how it arose.