The customer is always right. In 1961, working to support the government of Ngo Dinh Diem in South Vietnam, American military officials launched a new effort to understand their task. The organization then known as the Advanced Research Projects Agency—it has since added the word “Defense” to its name, becoming DARPA—decided to fund new programs in social-science research. The agency “needed studies performed that could answer questions that were confounding defense officials at the Pentagon,” Annie Jacobsen writes in her sprawling history of all things DARPA. “Who were these people, the Vietnamese? What made one Vietnamese peasant become a communist and another remain loyal to President Diem? How did these foreign people live, work, strategize, organize, and think?”

Given the historical roots of American involvement in Vietnam, 1961 was an awfully late date to be asking those questions. As the saga of DARPA unspools, this emerges as a depressingly familiar pattern.

In any case, Jacobsen notes, the agency began to throw some social science at Vietnam, contracting with the RAND Corporation for work on a “persuasion and motivation” project. At the beginning of 1962, the RAND-affiliated anthropologists Gerald Hickey and John Donnell arrived in Saigon, determined to plumb the motivations of America’s new imperial subjects. “Both men were eminently qualified anthropologists and spoke fluent Vietnamese,” Jacobsen writes. The two researchers began to investigate the Strategic Hamlet Program, a pacification campaign to separate South Vietnamese peasants from Communist guerrillas. Forcibly relocated, villagers had been settled behind “tall, fortress-like walls” and barbed wire. Strategic hamlets were supposed to solve two related problems with one set of barriers: Communists couldn’t influence people they couldn’t reach, and villages isolated behind walls couldn’t support a war they couldn’t touch. The two governments responsible for the program were pretty happy with it. “In the winter of 1962,” Jacobsen writes, “strategic hamlets were being erected at a rate of more than two hundred per month.”

But then Hickey and Donnell began to talk to the people who lived inside those hamlets. They quickly discovered that the program was a disaster: The hamlets had been built with forced labor, taking subsistence farmers away from the work of planting crops and threatening them with hunger. And the villagers proceeded to demonstrate the direct, physical failure of the attempt to isolate them: “A group of villagers showed Hickey and Donnell a deep underground tunnel that had been dug by the Vietcong. It ran directly under the perimeter defense wall and up into the center of the village. Vietcong could come and go as they wished, the villagers said. And they did.”

Some walls really were impassable, though. Finally arriving at the Pentagon to brief their government patrons at the highest levels, Hickey and Donnell sat down in the office of Harold Brown, the director of Defense Research and Engineering. As they described their findings to the government official who had paid for the project, Hickey would later say, Brown “swung his heavy chair around and looked out the window, leaving us to talk to the back of his chair.” He never turned back around; they finished the briefing and were shown the door in embarrassed silence.

Then the problem was solved. Brown complained to the president of RAND about the poor quality of its work, and new researchers were dispatched to South Vietnam from late 1962 through the summer of 1963. They reported that the strategic hamlets were working well and that the Communists were being crushed. American military officials were comforted to learn that their effort was going so well. By 1964, they realized, the American role in Vietnam could wind down and South Vietnam’s future would be secured. Social science had done its job.

A solider wearing military gear developed by DARPA’s warrior web program.
A solider wearing military gear developed by DARPA’s warrior web program. Us Army/Rdecom/Flickr

Jacobsen tells several deeply reported versions of this story, describing the collisions between an industry built to provide knowledge and a client that doesn’t actually want it. The nuclear strategist Leon Gouré, also employed by RAND on an ARPA contract, produced a series of reports after 1965 proving that “bombing was the pathway to victory in Vietnam.” The quality of these reports was widely appreciated—especially by the air force—even as other analysts, looking at the same research data, warned that those findings “simply were not there.”

Forty years later, American military officials running a war in Iraq similarly discovered that they didn’t understand the people they were fighting. Describing a conversation between “a science advisor to the Joint Chiefs of Staff” and an anthropologist on contract with DARPA, Jacobsen recounts the concerns the Pentagon expressed in 2004. “We have no idea how this society works,” the adviser confessed. “Could you help us?”

In Jacobsen’s careful telling, intellectual laborers in the hard sciences often face a results-indifferent mandate; the technological gee-whizzery of DARPA’s long involvement in the expansion of the American empire has also been driven by wishful thinking and the reliable geyser of the national-security budget. In Iraq, for example, improvised bombs built for the equivalent of twenty-five dollars were “responsible for 63 percent of all coalition force deaths.” So the Defense Department resolved in 2006 to confront an enemy that was readily supplying itself with a reserve of pilfered explosives by forming the Joint Improvised Explosive Device Defeat Organization (JIEDDO), with “a first-year budget of $3.6 billion.” By 2007, though “an estimated $15 billion had been spent . . . on counter-IED efforts—on jammers, robots, surveillance systems, and more”—IED attacks had doubled. The problems of war are somehow always a surprise, the response is somehow always a program to buy more gadgets, and the problems are somehow never solved.

In the ’50s, Jacobsen writes, the defense intellectual and military administrator William Godel formulated what he called his “bold summation” of the main challenge the nation would face in the coming decades: “Insurgents might have superior discipline, organization, and motivation, he said. But science and technology could give ‘our’ side the leading edge.” We’ve been chained to that rock ever since, replacing strategic thought with the certainty that machines can deliver victory: Invade, fight, buy some computerish new sciencey stuff, win. In Vietnam and the Middle East, the results of that odd faith are written on the landscape.

There’s a final sliver of analysis missing from this very good book: a deeper consideration of the wars that we stumble through under the banner of technological certitude. In 2004, the Pentagon asked an anthropologist to run some data sets and figure out Iraqi society, and, yes: It’s like Vietnam never happened. But that act of forgetting didn’t only happen inside the Department of Defense. The American war in Iraq began with a cultural premise: the insistence that Iraqis yearned for an American model of freedom and political pluralism. If the people fighting that war realized only in its second year that they didn’t understand the culture of the society they were trying to remake, then our problem is neither military nor strategic. It’s a basic political failure, a complete inability to discuss and understand the reasons we go to war. “We have no idea how this society works” is a thing to say before you invade, and the horrible timing of that admission was more than simply a result of bureaucratic dysfunction within the Pentagon.

Jacobsen digs deep into the assumptions of people trying to win wars by doing cool stuff in the laboratory, but the larger politics of her story sometimes get lost, understandably, in a narrative framed by science initiatives. The Pentagon’s Brain, focusing as it does on the scientists and administrators who run DARPA programs, leaves room for other writers who might pursue a more sustained inquiry into the cultural origins and political impact of our increasingly damaging belief that technology is a substitute for strategic wisdom.

But there is an important political observation in these pages. Like Shane Harris’s recent @War, Jacobsen’s book indicates the degree to which corporate interests drive policy decisions. The current efforts by the American military to solve battlefield problems with laboratory solutions are overseen by the Defense Science Board, a majority of whose members are defense contractors. Thus does an industry impaneled as an oversight board serve as the body expected to monitor its own efforts. To wit, Jacobsen writes:

DSB chairman Paul Kaminski, who also serves on President Obama’s Intelligence Advisory Board, is a director of General Dynamics, chairman of the board of the RAND Corporation, chairman of the board of HRL (the former Hughes Research Labs), chairman of the board of Exostar, chairman and CEO of Technovation, Inc., trustee and advisor to the Johns Hopkins Applied Physics Lab, and trustee and advisor to MIT’s Lincoln Laboratory—all companies and corporations that build robotic weapons systems for DARPA and for the Pentagon. . . . If DARPA is the Pentagon’s brain, defense contractors are its beating heart.

That’s a story that needs to be told, and The Pentagon’s Brain puts Jacobsen in the company of important writers who have supplied other versions of it, such as Harris and Rajiv Chandrasekaran. They seem to be describing the willfully obtuse wandering of a dying empire, but then somehow the thing still hasn’t died. Maybe we can revisit the question the next time we find ourselves fighting a war in a place we suddenly discover we don’t understand.

Chris Bray is a historian and former soldier.