At the New York Times and in commemoration of the centenary of the U. S. entrance into World War I, Michael Kazin muses over whether the U. S. should have entered the war at all:
How would the war have ended if America had not intervened? The carnage might have continued for another year or two until citizens in the warring nations, who were already protesting the endless sacrifices required, forced their leaders to reach a settlement. If the Allies, led by France and Britain, had not won a total victory, there would have been no punitive peace treaty like that completed at Versailles, no stab-in-the-back allegations by resentful Germans, and thus no rise, much less triumph, of Hitler and the Nazis. The next world war, with its 50 million deaths, would probably not have occurred.
I don’t think he dwells enough on the effects our entry into the war had on the United States or the reasons we entered the war.
The last justifiable war occurred in 1812.