Why We Fight: The Roots of War and the Paths to Peace

“Why We Fight is a tour de force of superb social science.”

Here is an interesting and provocative book that will make you wonder if the drug gangs in Medallíne are smarter than the rulers of Europe and Russia in 1914 or the Rumsfeld-Cheney-Bush cabal that chose to invade Iraq in 2003 or Vladimir Putin in 2022? The drug gangs have every incentive to fight for turf and glory, but seldom draw blood. Why? Like players in game theory, they calculate that the potential gains are not worth risking severe damage to existing material interests, image, and physical well-being. It is smarter to compromise and divide the spoils of peace.

So the main incentive for peace is the perceived cost of war. Despite this logic, five factors can and do push decision-makers to fight. First, their personal interests may outweigh for them the potential sufferings of their soldiers and followers. Not by accident, many signers of the Declaration of Independence had much to lose from British colonial policy—trade interests, vast western land holdings, ownership of slaves, and the local legislatures they controlled. Most Americans opposed a revolutionary war, but relatively few could vote.

Second, however, intangible values such as justice, honor, and religion may override survival instincts and material interests. Thus, peasants in El Salvador fight guerrilla-style against landlords because they resent their treatment—not because they hope to get more land. By contrast, rebels in Syria fought for a different intangible: freedom from the dictatorship. War is more likely when these five factors reinforce each other and are buffeted by an external event such as the assassination of the heir presumptive to the Austrian throne in June 1914.

Successful—peaceful—societies, according to Blattman, manage competition without war. They make the most of four factors: first, interdependence. In India’s coastal cities like Somnath, Muslims and Hindus have been socially interdependent and even started some joint business activities. Going back hundreds of years, Hindus encouraged foreign traders, Muslims, to settle down on land grants. They would carry local textiles to foreign ports. In such places there has been little Hindu-Muslim conflict.

Blattman cites many of the analysts who taught that trade would breed peace. Unfortunately, this hope has often proved illusory. All the great powers in 1914 were interdependent but proceeded to destroy their individual and shared prosperity.

Second, checks and balances help preserve peace. A stable society will have many centers. Dividing power and holding deciders accountable can reduce all five risks of war, while. concentrated power permits tyrants to take and abuse power.

Third, rules and enforcement can help. As Thomas Hobbes predicted, a Leviathan state can reduce anarchy; the Pax Romana and Pax Britannia were brutal but outlawed wars in their realms.

Fourth, outside interventions can help—deterring bullies, enforcing bargains, incentivizing, facilitating compromise

Blattman acknowledges the role played by threats of violence but is nearly silent on nuclear weapons, regarded by many analysts as the main bulwark of peace since 1945, but also as the major threat to civilized humanity. This silence is not proportionate to the dangers posed by vertical and horizontal nuclear proliferation.

Blattman’s final chapter is “the Piecemeal Engineer.” Since life is complicated, he warns against hoping for large-scale change. Instead, he says, “honor the margins”—strive for small, marginal improvements. His final advice parallels that of earlier generations of international relations scholars who advised, “be eclectic. Try various approaches and do what works in a particular time and place.”

Having read Blattman’s chapter on how gangs practice game theory to avoid war, a reader might wonder if any of Blattman’s recommendations could have prevented the “guns of August 1914.” The Iraq invasion of 2003, or Putin’s attack on Ukraine. The answer is no. Informed people in 1914 knew that war would be catastrophic for Europe, but the war began anyway. In 2003 and 2022 the U.S. and Russian governments failed to make a serious study of how long and how destructive their wars in Iraq and Ukraine could become. In these three cases one needs a psychiatrist to explain what happened rather than a game theorist.

Despite these cavils, Why We Fight is a tour de force of superb social science. It could be a research and study guide for graduate students. But its lively style and fascinating anecdotes would make it a good choice for any reader seeking to learn how the world works.