One of the joys of serving on the Naval War College faculty is the opportunity to bolt from the ivory tower from time to time and interact with a variety of audiences, from history or political-science specialists to everyman on the streets of rural America. World War I has been much on everyone’s minds of late because a century has elapsed since the guns fell silent: the Allied and Central powers concluded an armistice on November 11, 1918.

Early this month, to help commemorate the occasion, I traveled to Kansas City for the centennial symposium at the National War I Museum and Monument and delivered a talk about the war’s lessons for the U.S. Navy. On Sunday I rode up to Sharon, Massachusetts, for the second straight year to review the war’s legacy as part of the town’s Veterans’ Day observances. Afterward attendees repaired to the local VFW post for some fellowship.

The chief legacy of the Great War is that it ended in a bad peace. No one except France, which knew it was on the firing line as neighbor to a vengeful Germany, saw a compelling stake in the peace settlement concluded at Versailles. European powers wanted to preserve and expand their empires at the expense of the vanquished. The United States went into the war at President Woodrow Wilson’s behest to remake the world order shattered in 1914 and replace it with one founded on international law and institutions instead of raw power politics. It saw itself as an anti-imperial nation and had little interest in perpetuating colonial rule.

If the victors can’t agree on what a peace settlement should look like, chances are no one will invest military manpower or diplomatic or economic resources in enforcing it over the long haul. An unenforced peace typically proves perishable. That sad fate befell the Versailles settlement and the League of Nations, the multinational body that Wilsonians hoped would keep the peace. War returned to Asia by 1931, when the Imperial Japanese Army invaded Manchuria, and to Europe by 1939, when Nazi German and Soviet legions barged into Poland.

That peacemakers fell short at Versailles is an uncontroversial statement. It’s hard to maintain that a postwar order that lasts just over a decade before buckling under the impact of another great war constitutes a good peace. But I elicited some pushback from veterans gathered at the VFW when I suggested the peace terminating World War II wasn’t especially good either. Did it represent an improvement on the Versailles settlement? Indubitably. The United States made close friends out of defeated foes Japan and (West) Germany, helped rebuild Western Europe through the Marshall Plan, and co-founded history’s most successful alliance, the North Atlantic Treaty Organization. And despite its failings, the United Nations—the descendant of the League—debuted at San Francisco in 1945 and endures to this day.

But.

There was a reason Washington needed to summon up such efforts, and that was because the victors fell out among themselves once again. America needed to anchor itself in the European and Asian rimlands to stave off the third great war that loomed on the horizon shockingly soon after Japanese delegates inked the surrender on board the battleship Missouri. In March 1946 wartime British prime minister Winston Churchill traveled to Fulton, Missouri, to warn that the “iron curtain” of Soviet totalitarianism was descending to split Eastern from Western Europe. Around the same time the diplomat George F. Kennan dispatched a “long telegram” to the State Department proposing a strategy aimed at “containing” Soviet communism—a strategy administrations of both parties made their north star until the Cold War’s end in 1991.

Lions did not lie down with lambs following the triumph over the Axis.

So it’s true to say the Western allies acquitted themselves more admirably by far from 1945 onward than they had in 1918, when wartime amity splintered altogether. The same cannot be said of the Grand Alliance with the Soviet Union. In that sense World War II merits a cheer or two where the outcome of World War I merits none. But in this age of smoldering small wars in the greater Middle East and incipient great-power competition, it is worth asking what makes a durable and praiseworthy peace accord—and how to enforce it. We may need guidance from history sooner than we think.