The United States officially joined the ranks of the combatants in World War I on April 6, 1917—a bit more than 100 years ago. Our collective memory of the conflict, it seems, is rather foggy. Indeed, to most Americans today, “the war to end all wars” is pretty much amystery. We may vaguely remember from our history courses that it was the first “total war,” and the first conflict in which airplanes and tanks figured prominently. And of course, it was a war of trenches, poison gas, and horrendous casualties. The Germans were the bad guys, but not perhaps quite as bad as the Germans in the Other World War.

Newspaper stories and TV documentaries about the Middle East and the Balkans never fail to remind us that recent conflagrations in those regions have their origins way back in the First World War, when the victors redrew the map of the world in cynical ways. Yes, we are told again and again, World War I “shaped the trajectory of the contemporary world in many ways” . . . but how, exactly?

It’s hard to say, because we Americans have no generally accepted narrative of the conflict. The war’s causes remain murky and obscure, its ending inconclusive, and its legacies contested. 

Just what was America’s role in this tragic event? What effect did the war have on American society? We’ll turn to those questions after briefly exploring the contours of this mammoth conflict while America stayed on the sidelines, from August 1914 until April 1917.

Long before the opening salvos, imperial ambitions and mutual suspicion among Europe’s great powers made war a likely if unwelcome prospect. The complicated web of alliances among the key states encouraged mutual belligerence rather than stability. “Europe,” writeshistorian Barbara Tuchman in her classic account, The Guns of August, “was a heap of swords piled on delicately as jackstraws; one could not be pulled out without moving all the others.” ...