In the minds of many Americans, World War I was a first draft of World War II, fought with less advanced technology but otherwise similar. But the two wars were actually quite different. The earlier war was more or less a family squabble among the crowned heads of Europe; Kaiser Wilhelm was, in fact, Queen Victoria's grandson.
Thomas Fleming presents a strong case that there was no reason for the United States to enter World War I, and argues that if it had stayed out, it might have played a more effective role afterwards as mediator, preventing the excesses of the Treaty of Versailles and its disastrous aftermath.
Woodrow Wilson was reelected in 1916 on a platform of staying out of the war, but almost immediately committed the U.S. to the conflict. German submarine warfare is often cited as a factor provoking American entry; Fleming argues that it was no worse than the British blockade of Germany. In any event, the sinking of the Lusitania was a dubious causus belli, since the ship was carrying munitions.
Once America was in the war, civil liberties slipped to their lowest point since the Civil War, if not in all of U.S. history. The Sedition and Espionage Acts made criticism of the government a crime. The Post Office banned dissenting magazines. Critics of the war and the draft received lengthy jail sentences. Robert Goldstein was sentenced to ten years for producing an "anti-British" film about the American Revolution. A Lansing, Michigan man got twenty years for denouncing the war in a private conversation. Even a U.S. Senator, Robert La Follette, was the target of charges of sedition and treason. Bigotry against German-Americans was rampant; both Wilson and Theodore Roosevelt denounced "hyphenated Americans."
After the war, Wilson's diplomacy was ineffective. England and France wanted revenge and had little interest in the Fourteen Points. The final treaty contained little of what he wanted, but Wilson accepted it in the hope of carrying through its provision for a League of Nations. Having created a wartime atmosphere in which disagreement was tantamount to treason, Wilson attempted to get the treaty ratified by impugning Republicans' loyalty, but the technique backfired on him. He then suffered a debilitating stroke; at first without his knowledge and later with his active participation, his disability was systematically concealed from the public; yet Fleming tells us he attempted to get nominated for a third term. (Roosevelt emulated this pattern, with greater success, in 1944 -- but that's a matter for Fleming's other book, The New Dealers' War.)
In a time when our government is using threats from abroad as an excuse for reducing our liberties, a look at the events from 1916 to 1918 can provide perspective -- and give us a warning.