Alas, I think the situation is much worse than that.
If you take a broader view of war, one that encompasses the results of the peace process (and you absolutely should do so), the wars that the US “won” during the 20th century seem a lot more like defeats than victories.
It’s always hard to figure out why democracies fight wars, but if you analyze any of the stated justifications for the US entering WWI or WWII, you quickly notice that none of them were achieved during the peace processes. WWI hardly ended war – it did wipe out some monarchies, but that didn’t work out particularly well either. The war destabilized Central Europe, created the Soviets, and led (obviously) to the next World War. “Winning!”
If you review the Atlantic Charter, and take it as the expression of the US war aims for WWII, it’s hard not to laugh. In short, the peace process that followed WWII resulted in Soviet domination of Europe and Asia; Communist expansion in Eastern Europe, China, and much of the third world; and the immediate end of European Empires in a process that caused so much death and destruction in so many places (and continues to do so). If this be winning, it would probably have been worth finding out what losing would have been like. (More on this topic in a much longer post soon).
Under this broader view of military success, the US hasn’t won a war since we fought the Philippines. On the bright side, it was technically in the 20th century.