You may have hoped over the past couple of years to open the New York Review of Books and find a good long essay by Joan Didion cutting to the quick of the Trump campaign. How would the journalist who saw in Bill Clinton the "familiar predatory sexuality of the provincial adolescent" and in Newt Gingrich "one of the leading beneficiaries of the nation's cultural and historical amnesia" choose to excoriate Candidate Trump?

Perhaps it would have been too easy. Didion has always preferred the oblique approach to her subject. So how about coming at the Trump phenomenon from New Orleans nearly half a century before the fact? That's what Nathaniel Rich, writing in the book's introduction, thinks Didion accomplished in the notebook she kept on a road trip through Louisiana, Mississippi and Alabama in 1970, now published as "South and West."

The book's two titular sections consist of notes for pieces (Didion's preferred term) that were never written. And not many notes at that: a scant 120 or so small pages. Most of the book is given to the South, with Didion studying the weather, swimming in hotel pools, eating heavy meals, conducting interviews and skipping appointments. "California Notes" runs only 14 pages from the Patty Hearst trial (unsuccessfully covered for Rolling Stone) to familiar Didion tropes about misconceptions of the West and her relation to them.

It might sound like a volume best left to scholars and completists, except that Didion's notes are not like most writers' notes. The form suits her particular brilliance: the ability to sequence arresting sentences, crammed with observation and insight, and let them generate their own momentum.

Her best work is often elliptical and free-floating. "South and West" gets us, if anything, even more swiftly to one point after another. And from one improbable image to the next: Didion falling in the mud; Didion keeping a Confederate flag in her linen closet.

As for anticipating Trump, it's always easier to identify the causes after you know the effects. But it was Didion's stated hunch that the "psychic center" of the country was located on the Gulf Coast. She went down to investigate and came away writing: "When I think of New Orleans I remember mainly its dense obsessiveness, its vertiginous preoccupation with race, class, heritage, style, and the absence of style. As it happens, these particular preoccupations all involved distinctions which the frontier ethic teaches western children to deny and to leave deliberately unmentioned." Has any analysis of the election improved on this?

If this is how Didion's notebooks read, let's have them all.

Scott F. Parker is an author and book critic. He lives in Montana.

South and West: From a Notebook
By: Joan Didion.
Publisher: Alfred A. Knopf, 126 pages, $21.