Washington Post reporter Ann Gerhart’s book deftly answers all sorts of questions about this odd couple’s relationship. But well-reported and perceptive as it is, her book can’t help but leave readers with an unanswerable question: What on earth is she doing with him? Physical attraction is one thing–Gerhart details the “crackling chemistry” between these two attractive people who became engaged only six weeks after their first date, and married only six weeks after that. But don’t spouses normally have quite a bit more in common than the same junior high school in Midland, Texas?

The Perfect Wife is a short, breezy, guilty pleasure of a book, full of juicy quotes and anecdotes that will remind the reader that its author once wrote the Post’s “Reliable Source” gossip column. Gerhart clearly admires Laura Bush, whom she has covered since 2001. She praises her warmth, sincerity, intelligence, and loyalty. But this is no valentine to the First Lady. Gerhart offers an unflinchingly clear-eyed view of her subject’s foibles–never more so than when she describes the permissive, love-blinded parenting that has produced two of the worst-behaved offspring the White House has ever seen. Gerhart portrays the Bush twins, Jenna and Barbara, as careless young women who have used their Secret Service agents to tote their bags and arrange meetings with celebrities, when they aren’t trying to elude their protection altogether. “These girls have all the noblesse and none of the oblige,” is Gerhart’s pithy assessment.

Over and beyond the engaging portrait of Laura Bush and family offered here, there emerges a vexing question: How far into the post-feminist age are we going to continue this First Lady business, anyway? Isn’t it absurd to think that the most theoretically capable leader in the land–supposed to be highly intelligent, intellectually curious, thoroughly modern in every way–will have a spouse whose best skills are an adoring gaze and a knack for showing off Christmas decorations?

Given that America is now a place where, for instance, more women than men apply to medical school, this problem was waiting to happen. We saw it play out last time with Hillary Rodham Clinton in the White House. Recall the Clintonian promise of a two-for-one presidency, the health-care reform debacle, and the resulting operative phrases: too smart for her own good, doesn’t know her place, who does she think she is? Hillary’s act didn’t play well with many Americans, but at least we got an honest look at the inherent difficulties of First Ladyhood in the dual-career society. And Hillary, the last time we checked, didn’t seem to have been much daunted by the rage she generated among traditionalists. (And maybe we’ll find, someday, that the idea of a former president as First Gentleman finally puts this issue to rest.)

Meanwhile, in Laura Bush, we have someone who appears–at first glance–to be the anti-Hillary: a prim helpmeet who has buried all evidence of independent thought in order to give complete support to a husband whose beliefs, in many cases, are direct opposites of her own. The problem is that Laura Bush, as Gerhart makes clear, is much more than that caricature. She is a strong, independent, thoughtful woman with plenty of her own ideas which she cannot, or does not, articulate. That can get dicey at times, as when this passionately committed champion of books and privacy sits by, wordless, as the nation’s librarians protested the intrusiveness of the Bush administration’s Patriot Act.

Whatever that kind of accommodation may be doing to Laura Bush’s psyche (and she’s not about to tell), this arrangement works beautifully for her husband. In his words, “I have the best wife for the line of work I am in. She doesn’t try to steal the limelight.” And another time: “Laura is the perfect complement to a camera hog like me.” So, when she’s in her official capacity, she simply takes her intelligence underground. At times, the results are poignant–and, to Gerhart, disturbing.

“As I watched Laura Bush in those first months moving through her public events, I noticed how much more animated and commanding she was when acting solo. When she traveled with the president, she faded to background. It made me wince” And she also observed that when Laura Bush spoke in her official capacity or about her relationship to the president, she reverted to simple sentences, reminiscent of the Dick-and-Jane primers. On her initial impressions of her future husband: “I thought he was fun. I also thought he was really cute. George is very fun. He’s also slightly outrageous once in a while in a very funny and fun way, and I found that a lot of fun.”

But when she talked about books, or libraries, or education–her passions–her sentences grew far more complex. They became those of an accomplished grown-up.

Is it reasonable to believe that thinking 21st century women will keep playing this strange role for eight years (or even four)? Is it still acceptable for an American institution to insist, however implicitly, that a woman’s survival in her “job” include near-complete sublimation of her ideas? Is this only a problem when husband and wife are such wildly different people?

Gerhart quotes Hillary Clinton on the subject: Being First Lady “is really a complicated calculation. It’s very difficult.” And as gender roles grow farther and farther removed from the Mamie Eisenhower model (“Ike runs the country and I turn the lamb chops”), it’s not going to get any easier.