First World War

The First World War is used to show how the expectation of meeting the same opponents again can sustain cooperation even amid a larger conflict. Along the entrenched Western Front, British and German troops developed an unofficial, unspoken “live-and-let-live” system: for at least two years beginning in 1914, opposing groups often refrained from attacking one another. The example makes the war a case study in the “shadow of the future,” where an uncertain but extended prospect of repeated encounters could make restraint a practical strategy for ordinary soldiers.

The Front-Line Truce

The familiar image of troops fraternizing at Christmas—meeting and drinking together in no-man’s-land—was only the most visible instance of a broader practice. The more sustained feature was a series of unofficial nonaggression understandings along the front, which persisted for at least two years from 1914. They were unspoken rather than formal agreements, and their recurrence depended on soldiers facing the same opposing groups over time.

An account by a senior British officer captures the contrast between the practice and military expectations. Visiting the trenches, the officer was astonished to see German soldiers moving within rifle range behind their own line while British soldiers took no notice. The officer expected to stop such conduct on taking command and interpreted it as evidence that the Germans did not understand that a war was underway. Yet both sides appeared to be following the same live-and-let-live policy. The observation reveals a local understanding that could be legible to the soldiers involved while appearing inexplicable to an inspecting superior.

Repeated Contact and the Future

The conditions of entrenched warfare gave each platoon reason to expect continued contact with the same opposing group. A dug-in British unit might face the same dug-in German unit for many months, while ordinary soldiers could not know when, if ever, they would be transferred. Army orders were described as arbitrary and difficult for those receiving them to understand, leaving the duration of the encounter uncertain rather than fixed.

That uncertainty did not erase the future; it made the future long enough, and indeterminate enough, to support reciprocal restraint. In the book’s analysis, soldiers could behave like participants in a repeated Prisoner’s Dilemma: cooperation with the particular enemy group facing them could improve their own prospects, because each side’s restraint reduced the immediate danger to the other. A Tit for Tat-like pattern of cooperation could therefore take hold without either side needing a formal pact or a complete estimate of how long the arrangement would last.

Soldiers’ Stakes and Military Aims

The live-and-let-live system reflected a difference between what mattered to individual soldiers and what military leaders wanted. The generals’ preferred outcome was mutual defection: their troops should take opportunities to attack the opposing side. From the soldiers’ immediate perspective, however, mutual cooperation was preferable to mutual defection because they did not want to be shot.

This difference did not mean individual soldiers necessarily preferred their country to lose the war. They could favor victory over defeat in the abstract and still recognize that one soldier’s conduct was unlikely to determine the outcome of the whole conflict. By contrast, cooperation or defection toward the specific enemy soldiers across no-man’s-land directly affected the individuals who had to face one another. The local logic of survival thus diverged from the strategic logic of winning the war, giving the informal restraint its force and its limits.

Historical and Analytical Significance

The example extends the analysis of repeated cooperation beyond controlled games and into wartime conduct. The theory of games and the Prisoner’s Dilemma had not yet been formulated when the system developed; the book applies those ideas retrospectively, using the historical research of historian and sociologist Tony Ashworth and an analysis associated with Robert Axelrod. The soldiers’ conduct is presented not as proof that the war’s opposing aims had disappeared, but as evidence that a repeated, local relationship could create incentives different from those governing the war as a whole.

The episode’s significance lies in the scale at which cooperation operated. The war remained a conflict between states and armies, while the trenches placed particular groups in recurring contact, exposed to the immediate consequences of each other’s actions. Christmas fraternization offers a memorable scene, but the longer-running pattern matters more to the argument: restraint could become a practical response to an open-ended future, even where the larger institution demanded aggression.