Key Point: World War I reminds us that the consequences of war are extremely difficult to predict and often impossible to control.

For a long time, Americans have been branded as “isolationists” guilty of “appeasement” when they question the wisdom of starting or entering another foreign war.

The terms “isolationist” and “appeasement” are used to link today’s noninterventionists to the political leaders who, during the 1930s, did nothing to stop Hitler early on, when that might have been easy. Ever since then, starting or entering wars has been justified by claiming that the present situation is analogous to the threat from Nazi Germany and requires force.

The first problem with such a scenario is that Hitler’s rise to power owed much to a prior war: World War I, which was supposed to end war. That famous phrase appears to have originated with The War That Will End War (1914), a book by the British socialist author H. G. Wells. His dubious claim inspired cynicism early on. British prime minister David Lloyd George reportedly remarked, “This war, like the next war, is a war to end war.” Journalist Walter Lippmann said “the delusion is that whatever war we are fighting is the war to end war.”

Precisely because France and Britain entered World War I and were devastated — which none of the political leaders seem to have anticipated — people in those countries lacked the will for another war. They had also been lied to repeatedly by their political leaders, and they weren’t interested in going through that again. As far as Americans were concerned, the greed and hypocrisy of World War I belligerents discredited the idea of doing good by going to war, which is why Americans wanted nothing to do with another foreign war. It was because pro-war people lost their credibility during World War I that nobody responded when alarms were sounded about Hitler during the 1930s.

If popular sentiment now generally opposes starting or entering foreign wars, the people who deserve considerable credit are those “internationalists” who promote participation in wars that go wrong. Often there are terrible unintended consequences, because wars are the most costly, volatile, unpredictable, and destructive human events.

The Hazards of the Unforeseen:

World War I was probably history’s worst catastrophe, and U.S. President Woodrow Wilson was substantially responsible for unintended consequences of the war that played out in Germany and Russia, contributing to the rise of totalitarian regimes and another world war. American “isolationism” — armed neutrality would be a more accurate term — developed as a sensible reaction to his policies. After Germany’s initial advances into the Low Countries and France, the adversaries in World War I dug trenches and seldom advanced or retreated much from those lines.

German soldiers were generally outnumbered on the Western Front, but the Germans had smarter generals and more guns. The British navy enforced an effective blockade that made it difficult for the Germans to obtain many vital supplies, including food. Germany responded by building a submarine fleet, but it didn’t give them a way to invade Britain or the United States. By 1918, the war had been stalemated for more than three years, neither side able to force vindictive terms on the other. One of the last German offensives ground to a halt in the French countryside when German commanders couldn’t prevent their starving soldiers, amazed by the abundance of food, from gorging themselves on cheeses, sausages, and wine.

If the U.S. had stayed out of the war, it seems likely there would have been some kind of negotiated settlement. Neither the Allied Powers (France, Britain, Russia, Italy, Japan, and several smaller states) nor the Central Powers (Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria) would have gained everything they wanted from a negotiated settlement. Both sides would have complained. But a catastrophe would have been less likely after a negotiated settlement than after vindictive terms were forced on the losers.

Apparently Wilson wanted to demonstrate the global influence of the U.S. by presiding at postwar negotiations, but he figured he could do that only if the U.S. were a belligerent. He had offered his services as a mediator, but his prospective allies, the French and British, weren’t interested. As historian Barbara Tuchman reported, “It was not mediation they wanted from America but her great, untapped strength.”

French and British generals squandered the youth of their countries by ordering them to charge into German machine-gun fire, and they wanted to command American soldiers the same way. Those generals repeatedly demanded that Americans reinforce their depleted ranks and fight under French and British flags. America’s first great struggle in the war was with the French and British, who feared that if American soldiers went into battle as an independent force under American command, they — not the French and British — would get the credit for success.

On April 2, 1917, when Wilson went before Congress to seek a declaration of war, he wasn’t trying to protect the United States from an attack or imminent attack, although there had been provocations. His stated aim was to destroy German autocracy. He urged “the crushing of the Central Powers.” He famously promised that the world “would be made safe for democracy.”

The U.S. played a significant military role only during the last six months of the war, but that was enough to change history — for the worse. By entering the war on the side of the French and British, Wilson put them in a position to break the stalemate, win a decisive victory, and — most important — force vindictive surrender terms on the losers.

The Frontiers of Control:

Wilson seemed unaware of two critical limits of his power. First, since he represented the largest and richest belligerent, he assumed he would be able to control what his allies did, but he couldn’t, and they hijacked the postwar negotiations. French Prime Minister Georges Clemenceau was determined to avenge Germany’s humiliating defeat of France in 1870 — a war that France had started. Clemenceau wasn’t to be denied, since most of the fighting during World War I took place on French soil and the French suffered some 6 million casualties. He made sure the Versailles Treaty obligated Germany to pay huge reparations and surrender a long list of assets including coal, trucks, guns, and ships — private property as well as property of the German government.

Despite Wilson’s professed ideals about the self-determination of peoples who had been in multinational European empires, he didn’t stop the Allies from dividing German colonies among themselves. British Prime Minister David Lloyd George expanded the British Empire by seizing the former German colonies of Tanganyika and part of Togoland and the Cameroons. The French and British each gained authority over some territories of the defunct Ottoman Empire.

The French and British bribed Italy to enter the war on their side by signing the secret Treaty of London (April 26, 1915) that promised Italy war spoils in Austria-Hungary, the Balkans, Asia Minor, and elsewhere — and the Italians wanted it all. They were outraged to find that the French and British planned on giving them little. The Japanese demanded Chinese territory and a statement affirming racial equality, and while they didn’t get those things, they ended up receiving German assets in China’s Shantung province, including a port, railroads, mines, and submarine cables.

The second critical limit of Wilson’s power was that he couldn’t control what the losers did. For a while this didn’t seem to matter, since the Germans had been decisively defeated, their weapons were taken away, and they were broke.

The vindictive surrender terms, made possible by American entry in the war and enshrined in the Treaty of Versailles, triggered a dangerous nationalist reaction. Hitler was able to recruit several thousand Nazis. Allied demands for reparations gave Germans incentives to inflate their currency and pay the Allies with worthless marks. The runaway inflation wiped out Germany’s middle class, and Hitler recruited tens of thousands more Nazis by appealing to those bitter people whom he referred to as “starving billionaires” — they might have had billions of paper marks, but they couldn’t afford a loaf of bread.

What Might Have Been:

Suppose, for a moment, that the United States had stayed out of World War I, and instead of a negotiated settlement there was a German victory on the Western Front. How bad might that have been? The Germans showed how harsh they could be in the Treaty of Brest-Litovsk (March 3, 1918) in which, as a condition for ending the war on the Eastern Front, they gained large chunks of territory including Ukraine, Georgia, Finland, and the Baltic states. If Germany had won on the Western Front, it would have acquired some French territory and maybe Belgium.

The Germans probably wouldn’t have been able to enjoy their victory for long. Britain would have retained its independence, protected by its navy that might have continued the hunger blockade against Germany. In all likelihood, Germany would have become bogged down in endemic conflicts along the frontier with Russia, complicated by nationalist rebellions in the wreckage of Germany’s ally, Austria-Hungary. Such problems might have proven to be too much for the German army that was already struggling to put down mutinies. Bad as this would have been, even it was preferable to what did happen: the rise of Hitler, World War II, and the Holocaust.