It was rather naively—and mistakenly—called the War to End All Wars. And although it hardly put an end to armed conflict, World War I did have a profound effect on this nation and the world.

Today marks the 100th anniversary of America’s entry into this bloody conflict, and many argue that without our involvement, the outcome may have been quite different.

For nearly three long years, the great European powers had slugged it out to a virtual stalemate. The introduction of American doughboys—who began arriving in France in June of 1917—to the trenches finally tipped the scales in favor of the Allies. When the war finally ended on Nov. 11, 1918, more than two million American soldiers had served on the battlefields of Western Europe and some 50,000 of them had lost their lives.

The war changed the prevailing world order. Gone were kings, czars and sultans. New nations rose from the ashes. No longer would war be fought merely between rival armies: seven million civilians also lost their lives. The philosophy of the factory amped up the scale of the slaughter, with machine guns, chemical weapons and airborne bombing just some of the technological innovations designed to maximize carnage.

World War I also gave us a hope, however fleeting, that this insanity would not be repeated. In the days after the war, a League of Nations set about to make sure that civilized nations would work their problems out by negotiation, not war. That hope died with the rise of the Nazi Party in Germany.

On this centennial observance, let us hope that we will see in our lifetimes an end to war.