Tony Perry / Los Angeles Times

“The Insurgents: David Petraeus and the Plot to Change the American Way of War” by Fred Kaplan (Simon & Schuster, 400 pgs., $28)

Everyone knows — or thinks they know — about the influence exerted by the military-industrial complex on American foreign policy.

But there is also a military-intellectual complex composed of think-tank researchers, policy theorists, academics, Pentagon bureaucrats, officers with PhDs, and even a few columnists. It was this complex that greatly influenced America’s military strategy in Iraq and Afghanistan.

That, at least, is the thesis of a serious and insightful new book by Pulitzer Prize-winning author Fred Kaplan: “The Insurgents: David Petraeus and the Plot to Change the American Way of War.”

In telling detail, Kaplan explains how Petraeus and like-minded thinkers worked to shift U.S. policy in Iraq from one that primarily relied on a heavy use of force to one that combined a more nuanced use of force with an emphasis on protecting the civilian population and, yes, winning hearts and minds.

Instead of defining success by how many enemy were killed, the new policy, under the flexible description of counterinsurgency, aimed at helping the government in Baghdad and the provincial capitals win the support of their own people with jobs programs and infrastructure projects.

The policy change did not occur quickly or without opposition. Defense Secretary Donald Rumsfeld was not a believer. He refused to even admit that an insurgency had gripped Iraq after the fall of Saddam Hussein. After Vietnam, the phrase “nation building” had become repulsive to many high-ranking officers.

As Kaplan sees it, the counterinsurgency strategy saved the U.S. from defeat in Iraq but probably will not work in Afghanistan. He praises Petraeus for championing the change of strategy in Iraq but faults him for not warning President Obama that he was not providing enough time or troops for a similar effort to be successful in Afghanistan.

Beginning with his days at West Point, Petraeus was interested in counterinsurgency theory as developed by British and French military writers — which points to the irony of Kaplan’s title: Petraeus and the others were “staging an insurgency against the ‘big Army’” and its reliance on massive firepower.

Although he failed to get a combat assignment during the 1991 Persian Gulf War, Petraeus excelled at networking and conducting inter-office warfare by Power Point presentations.

Kaplan’s book was written before Petraeus resigned as director of the CIA and admitted an extramarital affair with his biographer, Paula Broadwell. But news coverage makes clear that Broadwell was a member of the military-intellectual class that Petraeus liked to have around him.

The “who said what to whom in what meeting” approach to journalism can be stultifying. But Kaplan keeps his story moving with mini-profiles of the many laptop warriors who came to shape U.S. policy and how their paths interconnected.

Though Kaplan lists more than 100 interview subjects, he apparently did not interview any of the Marine generals from Iraq or Afghanistan. “The Insurgents” gives the impression that the Marine Corps largely exists in a parallel universe from the Army — not tied to the world of seminars, monographs and heated intellectual discussions.

Not waiting for the Army to shift its policy the Marines in 2004 went to Anbar province, the heart of the Sunni insurgency, carrying copies of their Small Wars Manual from the 1930s, which Kaplan lists as one of the early texts about counterinsurgency. By the time Petraeus and his field manual arrived in Baghdad in 2007, Anbar had gone from lost cause to virtual showpiece.

Quibbles aside, “The Insurgents” seems destined to be one of the more significant looks at how the U.S. pursued the war in Iraq and at the complex mind of the general in charge when the tide turned.