JOIN THANASSIS CAMBANIS and author FRED KAPLAN in a LIVE TWITTER CHAT on WEDNESDAY, JANUARY 30 at 1:00PM EST – Use #TheInsurgents to join, ask questions, follow the conversation. 

(Cambanis’s New York Times review of The Insurgents: David Petraeus and the Plot to Change the American Way of War) 

(Cambanis and TCF fellow Michael Cohen debate The Insurgents and post-invasion Iraq)

The Pentagon finally learned to embrace new ideas. Can its short-lived revolution in thinking survive the coming period of austerity and retrenchment?

The American military has maintained global dominance in part by being all things to all people. Blessed with a Brobdingnagian budget, it has been able to prepare for all kinds of war, all at the same time. Faced now with cuts after a decade of open-handed war funding, the Pentagon has raised the alarm about readiness. The Joint Chiefs of Staff in a unanimous letter in January complained to the president that “we are on the brink of creating a hollow force.”

The debate over the size and mission of the military often obsesses about questions of degree: should the United States be able to fight two major wars at the same time? Should it design a force that can fight many small wars?

But this debate, driven by budget-hungry service chiefs and tradition-hemmed academics and think-tankers, might be ignoring a far more important turning point facing the Pentagon today, which has more to do with mindset than money. Can the Pentagon retain the one truly good thing it acquired along the way in the bungled war on terror, Afghanistan, and Iraq—a possibly short-lived ability to learn?

Fred Kaplan’s new book, The Insurgents: David Petraeus and the Plot to Change the American Way of War, which I reviewed in the New York Times this Sunday, chronicles a chilling intellectual history of the officers who promoted counterinsurgency doctrine and eventually forced change among the Pentagon’s top brass. Kaplan is a skeptic, but his story reveals just how deeply hidebound the generals are, and how they were forced—through failure—to criticize themselves and adjust tactics.

Can this new mindset take root and become part of the Pentagon’s DNA, or is it destined to vanish as the generals who briefly dallied with self-awareness and adaptation now retrench around the common cause of budgetary self-preservation?

Listening to the current chairman of the Joint Chiefs of Staff, General Martin Dempsey, isn’t reassuring. Half a decade ago in Baghdad he eschewed BS, acknowledging the burgeoning failure and once telling a group of us reporters bluntly that “there isn’t enough concrete in the hemisphere to make Baghdad safe.” Now he’s stumping for wild defense budgets based on a spurious claim that the world is more dangerous than ever before and that we face an infinite menu of threats. Dempsey’s about-face doesn’t bode well.

For all the pitfalls of the war on terror, a decade of coalition-building and counterinsurgency forced the military to adapt and open itself up to new methods with an alacrity not seen since World War II. It was a wrenching internal fight between rigid generals, abstract bureaucrats, and junior officers open to experimentation and self-criticism, which Kaplan documents in vivid detail.

In The Insurgents (published in January), Kaplan argues that the U.S. military, perhaps inadvertently, discovered on the battlefields of Iraq and Afghanistan a new ability to learn. Now that the United States has moved away from those wars, Kaplan says, it is also throwing out what might be their only good legacy: imagination and flexibility in the Pentagon’s upper reaches.

His argument comes at a crucial time. President Obama last year ordered the Pentagon to cut off its budget for nation-building and long-term occupations of foreign lands—but he also instructed it to preserve the lessons it learned fighting counterinsurgencies in the Middle East. Many of the young officers who created a vogue around counterinsurgency in military circles grew just as dogmatic in their thinking as the older bureaucrats and officers who at first resisted new thinking, a sad process evident to any close observer of the slow failure of U.S. efforts in Afghanistan.

But they succeeded—at least in the last few years—at changing the military’s internal culture in ways far more consequential than the line item for a new bomber. They convinced the Pentagon to promote top generals who excelled in combat rather than those who had dutifully served in logistics and office posts. They reinvigorated the intellectual centers of military thinking, in particular the web of institutions from Fort Leavenworth to West Point that educate officers, write the military’s doctrine, and drive much of America’s strategic thinking. And they injected a strain of strikingly inventive utilitarianism—whatever works—into a vast defense bureaucracy that’s designed to protect fiefdoms rather than create new ideas.

Now, with the bloated war budgets ending and sequestration in site, a clear war of ideas is underway in the Pentagon: the old way, exemplified in the joint chiefs’ demand for big budgets, big weapons systems, and the same old lack of priorities, versus a fledgling new can-do culture that values the military’s ability to learn and adapt over its arsenal and size.

Let’s hope that creativity wins out. But I wouldn’t bet on it.