Minus U.S. reinforcements on land and sea, it’s difficult to imagine how the Allies could have defeated a Germany that had knocked revolutionary Russia out of the war....The exhausted Allies would have had to negotiate some kind of settlement with Central Power forces occupying almost all of what is now Ukraine, Poland, and the Baltic republics in the east; most of Romania and Yugoslavia in Southern Europe, as well as a bit of Italy; and almost all of Belgium and most of northeast France. Even if the Germans had traded concessions in the West to preserve their gains in the East, the kaiser’s Germany would have emerged from such an outcome as the dominant power on the continent of Europe. The United States would have found itself after such a negotiated peace confronting the same outcome as it faced in 1946: a Europe divided between East and West, with the battered West looking to the United States for protection. As in 1946, the East would have been dominated by an authoritarian regime that looked upon the liberal and democratic Anglo-American West not just as a geopolitical antagonist, but as an ideological threat.

But unlike in 1946, when the line was drawn on the Elbe and the West included the wealthiest and most developed regions of Europe, this imaginary 1919 line would have been drawn on the Rhine, if not the Scheldt and the Meuse, with the greatest concentration of European industry on the Eastern side. Unlike in 1946, the newly dominant power in Eastern Europe would not have been Europe’s most backward major nation (Russia), but its most scientifically and technologically advanced nation (Germany). In other words, the United States would have gotten an early start on the Cold War, and maybe a second hot war, supported by fewer and weaker allies against a richer and more dangerous opponent—and one quite likely to have developed the atomic bomb and the intercontinental ballistic missile first.

The question confronting the United States in 1917 was the same question that confronted Americans in 1941, and again after World War II, and now again as China rises: Who will shape world order? The United States and its liberal democratic traditions? Or challengers impelled by aggressive authoritarian ideologies of one kind or another?

Americans are susceptible to the belief that their country is somehow not a state like other states: It is either something purer and higher, or something unforgivably worse. If it’s not fighting “to end war,” in the rash phrase often (mistakenly) attributed to Wilson, then it’s fighting for J.P. Morgan and the munitions makers. Yet there was one of Wilson’s genuine phrases that did aptly describe what the issue was in 1917, and what it has been ever since. In his April 2 speech to Congress asking for a declaration of war on Germany, Wilson insisted that the “world must be made safe for democracy.”

Not “democratic”—“safe for democracy.” Wilson wasn’t promising to impose democracy on Imperial Germany. He was promising to defend democracy from Imperial Germany....Had the Western Allies lost the First World War, European democracy would have failed the test that American democracy surmounted in the Civil War: the test of survival in the competition between nations and regimes.

That said, yeah, it's amazing how every war basically gets sold to the public at least partly on the basis of lies and/or exaggeration.