What did America gain from winning world war 1?

Nothing. Absolutely nothing. Zero, zip, zilch, nada, butkus. Over 100,000 dead, more hundreds of thousands wounded and maimed, disability pensions, widows pensions and continued medical care for decades, treasure poured out like water, people imprisoned for protesting the war and the Constitution tortured to make it legal to lock them up. But its hard to think of any positive result. The Germans might have won if the US did not enter the war, and a Europe dominated by Wilhelmine Germany would not have been a nice place, so I guess there's that. We stopped the Kaiser, and made way for Hitler and Mussolini.