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17 October 2023

Why we go to war

Two new studies of the evolution of warfare reveal the fragility of peace in a world ruled by irrational actors.

By Elliot Ackerman

“Only the dead have seen the end of war.” Those words, attributed to Plato, are referenced conspicuously in two new wide-ranging overviews of warfare: Conflict: The Evolution of Warfare from 1945 to Ukraine, co-authored by the former director of the Central Intelligence Agency General David Petraeus and the British historian Andrew Roberts, and On Wars by the sociologist Michael Mann.

Plato’s observation is central to each book. If war is a fixture of the human condition, how might we better understand it? And to what end? With a war grinding on in Ukraine, and a new war begun in the Middle East, the questions raised in these books are urgent. The authors take different approaches to answering them. They also reach divergent conclusions.

In Conflict, the pairing of Roberts with Petraeus is an engaging choice. In the former you have a pre-eminent military historian and biographer of wartime leaders such as Winston Churchill and Napoleon, and in the latter you have perhaps the most pre-eminent military officer of his generation, who presided over the wars in Iraq and Afghanistan. This book, however, is not a full history, but a study of war’s evolution from 1945 to the present. Petraeus and Roberts have chosen this period because “strategic concepts have evolved faster since the Second World War than at any comparable period in history”.

[See also: The Rise and Fall of the Great Powers redux]

Petraeus and Roberts analyse more than a dozen conflicts from Borneo to the Balkans, tracing warfare’s progression – and, at times, regression – from one conflict to the next. They identify four key strategic tasks required by leaders to win wars, the most fundamental of which is “to comprehensively grasp the overall strategic situation in a conflict and craft the appropriate strategic approach – in essence, to get the big ideas right”. 

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As history shows, understanding a war’s “big ideas” is not a simple task. This is because neither side ever fundamentally agrees about the reasons the war is being fought – if they did, they wouldn’t be fighting the war. In the Vietnam War, for instance, which took place between 1955 and 1975, Petraeus and Roberts illustrate how American leaders subscribed to “domino theory”, viewing that war through the prism of a transnational communist threat. But the Vietnamese communists saw things differently. The authors quote the former US secretary of state and former chairman of the joint chiefs of staff Colin Powell, who observed, “We should have realised that it was a war as much about nationalism and self-determination within this one country as it was about the ideology of communism or the worldwide communist conspiracy.” In this case, the price for getting the big idea wrong was defeat. It’s a pattern repeated time and again in their book.

The first half of Conflict reads like a history, while the second half reads like a memoir, or journalism. In the chapters dedicated to the wars in which Petraeus was a participant, the tone abruptly shifts, with Petraeus taking us inside his thinking process as he struggles to adhere to the principles of leadership he outlines with Roberts in the book’s opening chapters.

In Iraq, Petraeus is duly critical of the Bush administration’s lack of planning after the invasion’s initial success in 2003. He recalls: “When, during the final gathering of commanders before the invasion I asked if the Office of Reconstruction and Humanitarian Assistance could provide additional information about what would happen after we got to Baghdad and toppled the regime, I was told, ‘You just get us to Baghdad, Dave, we’ll take it from there.’”

Petraeus does, however, credit George W Bush for shifting the course of the war. Once Bush committed to the surge, which Petraeus commanded between 2007 and 2008, he, along with the US ambassador to Iraq, Ryan Crocker, would brief the president daily and directly on their progress. Petraeus characterises these meetings as “a powerful demonstration of Bush’s commitment”.

[See also: The fatal flaw in the “final” Beatles song]

He is bipartisan in his critiques of America’s wartime presidents. When it comes to Afghanistan, he faults President Barack Obama for announcing his surge in the same 2009 speech where he announced the date by which American troops would be drawn down. This proved a disaster. “There was nothing wrong with establishing a tentative withdrawal timeline as a planning tool, but the public announcement of it sent a signal to the Taliban that they could hunker down and wait out the surge.”

In Conflict, such conclusions are not offered as a means of political score-settling. It’s no secret that Bush bungled the occupation of Iraq, nor that Obama’s decision to surge in Afghanistan in 2009 while simultaneously announcing the schedule for withdrawal undercut America’s military efforts. What gives these observations new resonance is that they’re placed into the broader context of warfare’s evolution and future. The book’s final chapter contains a series of warnings for contemporary military strategists.

One such warning concerns the importance of deterrence, which, loosely defined, is the threat of force used as a tool to dissuade a potential adversary. “No superpower can afford to be isolationist,” Petraeus and Roberts warn, echoing the realist school of political science. “Money spent on deterrence is seldom wasted, especially when considered against the costs incurred when the deterrence fails.”

This undercurrent of inevitability, a theory that war is, and forever will be, a human enterprise, places Conflict philosophically apart from On Wars. Michael Mann’s book has an ambitious scope, much like his four-volume The Sources of Social Power (1986-2012). In his latest, comparatively slim 500-page volume, Mann sets out to craft a “general theory of war” through a vast taxonomy of conflicts that spans continents and millennia. At the outset Mann concedes that even he isn’t convinced this is entirely possible.

He begins this journey by challenging Plato’s assertion that “only the dead have seen the end of war”. War, according to Mann, is not baked in to the human condition; rather, it’s a learned societal behaviour.

[See also: The realists were right]

His attempt to prove this relies on circular reasoning which concludes that “more than 95 per cent of the 150,000 years of humans living on Earth had passed before the appearance of warring states. This means that warfare is not genetically programmed into us. Biology is not destiny; we are doomed to warfare not by genes, but by societies.”

There’s a hole in this logic. Yes, 95 per cent of human history passes before we see the emergence of warring states. But it’s the same chunk of history that passes before we see the emergence of states themselves. Strangely, Mann follows this assertion by acknowledging that “pre-state communities contained interpersonal violence but only rarely warfare”. These arguments are puzzling and, made in the first 20 pages of On Wars, give the impression of a semantic game that feels unworthy of the book’s Clausewitz-ian title.

Mann, like the Prussian general and military theorist Carl von Clausewitz (1780-1831), is interested in warfare’s inherent unpredictability, what the latter termed “the fog of war” and what Mann characterises as “irrationality”. On Wars rejects realist political theory, which seeks to understand wars through rational cause and effect. This is welcome. The realists too often diminish the roles of emotion, irrationality and miscalculation when trying to understand the root causes of war. The realist belief that most of the time nations act rationally, in support of their well-articulated interests, lacks even a cursory understanding of human nature; the fact is that most people – and nations – struggle to understand their best interests. History is a narrative of humanity in a frenzy of emotion choosing ill-advised wars.

Mann understands the role societal narratives play in war. He asks, “Can you ‘narrate peace’?” His answer is to create an expansive narrative of war and to stitch together the gaps to create his narrative of peace. However, there aren’t many gaps. Humanity’s history is blood-soaked. Look at the past two years, from Afghanistan to Ukraine to the fighting between Israel and Hamas.

There are some exceptions. Mann points to China between the 14th and 19th centuries, a period when its emperors relied on “defensive, diplomatic imperialism”, which resulted in only a handful of wars. Less compellingly, he points to post-colonial Africa as an example of minimal state-on-state violence. He does this while discounting the continent’s myriad civil wars, as if organised slaughter between states were ontologically distinct from organised slaughter within states. Too often when advancing his arguments, Mann relies on an overly narrow definition of warfare. 

Unlike Clausewitz’s On War (1832), which is a primer for military strategists, the presiding spirit of Mann’s On Wars is Immanuel Kant. It’s preoccupied with understanding war so that humanity might someday transcend it and enjoy what in the 18th-century philosopher Kant imagined as “perpetual peace”, a world in which the strength of global institutions and norms eliminates war. This is a noble goal, one Mann shares with Petraeus and Roberts. Yet the two books present divergent views as to the best way to establish more peaceful societies.

[See also: The Middle East on the brink]

Petraeus and Roberts advocate for deterrence, peace through strength. Although Mann doesn’t argue against deterrence, he makes the case for a society where rulers “fully commit to international institutions”, ones that would not only deter war but would also collaborate on other critical issues such as climate change. Mann imagines a world in which rulers “calculate carefully what is self-defence, calm the emotions and the temper, never demonise potential enemies, consult advisers of varying views, and use soft power unless attacked”. If these guidelines are followed, Mann believes “there will be no more wars”. 

Mann is probably right. There would be no more wars if humanity was capable of all that. But it’s difficult to believe that this degree of rationalism is possible after having read his exhaustive history, one defined by humanity’s dogged irrationalism and the hot-blooded decision-making that attends war. Mann’s relentless narrative of war, one filled with savagery, subverts rationalism too effectively to allow us suddenly to believe that rationalism can then become the prescription for a perpetual peace. 

Petraeus and Roberts examine the war in Ukraine, one fuelled by Vladimir Putin’s irrationality and miscalculation, “which will be taught in staff colleges for decades to come as providing a masterclass in how not to fight a war”. Unlike Mann, Petraeus and Roberts spend little time imagining a world without war, or even a world with less war. Their book – like Clausewitz’s canonical text – is a primer for today’s strategists, brimming with lessons about leadership, counter-insurgency, and intelligence. It’s a guide to effectively prepare for and win wars of the future, to achieve perpetual peace through perpetual strength.

Conflict ends with an examination of future war. The book warns that in coming decades militaries will fight across an increasing number of dimensions. If the 20th century made air the third dimension of warfare after land and sea, then the 21st century promises to cement space and cyberspace as the fourth and fifth. To avoid living in a world dominated by rising authoritarian nations, and to ensure the perpetuation of a liberal world order, democracies will have to develop and invest in new weapons and technologies. Methods will change, but Petraeus and Roberts are clear-eyed about war’s enduring appeal as a policy tool, and the costs of deterrence, our best defence. “The amount of money that needs to be spent might seem vast, but historically it has always proven to be a mere fraction of what it costs in blood and treasure when deterrence fails.”

Still, this pragmatic assessment of war, and of its cost to humanity, left me craving a more elevated solution to our problems. Petraeus and Roberts aren’t wrong; they are, in fact, depressingly right about war, deterrence, and the costs of both. Mann understands those costs too. His book nobly reaches for a solution it never quite grasps.

Mann quotes the soldier-statesman Dwight Eisenhower, the US president from 1953 to 1961, who understood well what it means for a society to prepare for war. “Every gun that is made, every warship launched, every rocket fired signifies, in the final sense, a theft from those who hunger and are not fed, those who are cold and are not clothed. This world in arms is not spending money alone. It is spending the sweat of its labourers, the genius of its scientists, the hopes of its children… This is not a way of life at all, in any true sense. Under the cloud of threatening war, it is humanity hanging on a cross of iron.”

Conflict: The Evolution of Warfare from 1945 to Ukraine
David Petraeus and Andrew Roberts
HarperCollins, 544pp, £26

On Wars
Michael Mann
Yale University Press, 616pp, £30

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[See also: The tragedy of John Mearsheimer]

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This article appears in the 18 Oct 2023 issue of the New Statesman, War on Three Fronts