A century ago, war raged across Europe. Millions of soldiers and civilians died in the epic conflict of World War I.

In the first year of the fighting, however, something remarkable happened: On Christmas Eve, soldiers put down their weapons, climbed out of their trenches, and met in no-man’s land.

On what was normally a lethal field of fire, they broke bread.

British, French, and German soldiers also sang Christmas carols, swapped cigarettes, and played games of soccer.

A Scotsman who participated in one of these spontaneous celebrations called it “a short peace in a terrible war.”

The generals didn’t like the Christmas Truce of 1914. They condemned it as fraternization. After the war pushed its way through nearly four more years of carnage, the small miracle of that first Christmas stood out as a unique moment.

Does it hold lessons for today?

Of course it does: It reveals the power of Christmas and the impulse for peace, even in a place and time of murder and madness.

War breaks out for many reasons, from territorial ambition to economic gain. Scholars commonly blame the outbreak of World War 1 on a shaky balance of military alliances.

Peace erupts over food—or at least it can. During the Christmas Truce of 1914, it happened over meals of plum pudding, shared between erstwhile enemies.

Today, we live in a war-torn world. Nearly 50,000 people have died in Syria this year, as well as more than 20,000 in Iraq and more than 10,000 in Afghanistan, plus thousands more in Nigeria, Somalia, Yemen, and elsewhere.

Last year, Matthew O. Jackson and Stephen Nei of Stanford University studied the causes of peace and made an empirical observation: The trade of goods and services across international borders limits the threat of war.

“International trade induces peaceful and stable networks,” they wrote. “Trade increases the density of alliances so that countries are less vulnerable to attack and also reduces countries’ incentives to attack an ally.”

That sounds like a nice theory, but Jackson and Nei do more than speculate. They actually prove it to be true. Their paper, published in the Proceedings of the National Academy of Sciences, overflows with facts, figures, and equations.

Nowadays, people occasionally claim that democracies don’t go to war with each other. This is sometimes called the “theory of democratic peace.” There’s a bit of truth in it. Yet Jackson and Nei point to a deeper reality: “Once one brings trade back into the picture, it seems that much of the democratic peace may be due to the fact that well-established democracies tend to be better-developed and trade more.”

Hindsight allows us to say that war struck Europe in 1914 because a complex set of military agreements made it impossible to avoid a deadly crisis. If the major powers of the era had focused on free trade rather than fighting, perhaps the spirit behind the Christmas Truce of 1914 would have been a long-term reality rather than a short-term blessing.

Our task, of course, is to apply the lessons of the past to the problems of today. The takeaway point of Jackson and Nei’s research is simple: If we want more peace, then we should seek more trade.

Jackson and Nei conclude the way academics always do, with a call for more research: “The broad prediction of increased trade interests enabling more cooperative behavior overall would be interesting to explore more generally.”

That’s fine. Let’s go ahead and continue looking at the connections between peace and trade.

But also, let’s trade—and maybe have a worldwide Christmas Truce all year long.