This works against the USA.
I mean, zoom back toward 1914. The World System of Alliances had ensnared the USA and the CSA. If the CSA had not survived the Civil War, say by not seceding in the first place (no Ft. Sumter). The USA might well have supported the United Kingdom and France.
Obviously, it didn't happen that way: The UK and France screwed the United States by putting troops in the Confederacy. It was perhaps inevitable that Otto von Bismarck and later, Kaiser Wilheim, would include the United States in the Four Powers, and that the United States would crush first the Confederacy and then Canada, while Germany would begin with Russia and follow with France.
There would not be 62 States of the United States--No States of Cuba, Bahamas, Columbia, Lincoln, etc. Indeed, there might still be foreign governments playing in South America. It's hard to imagine that the defeats in 1862-4 and the defeat of President Lincoln would ultimately lead to an incredible conquering spree in the aftermath of the First World War. There would be no Treaty of New York signed in a fishing trawler in sight of the Statue of Liberty.
That Treaty of New York, along with Brest-Litovsk, Treaty of Kiel, and three Empires Agreement, would create a second world war of unimaginable proportions, a firestorm that broke Germany and nearly broke the USA. In a deep thirst of revenge, the USA and Germany, with support from Austria Federal Republic and the Ottoman Sultanate, did many things that would never have happened if the USA had never launched the war. We would never have dismembered the United Kingdom, breaking it back into England and forcibly liberating Ireland (Good US Ally) and Scotland (Lukewarm Ally). We would never have gutted Italy by Giving Austria all of Lombardy. And then the colonies--for goodness sake, so many nations and protectorates that could not work.
And this does not even begin to mention what happens when Thorez, Moseley, Stalin and Mussolini came to power.
There are those who say the the United States should never have begun on its imperial ambitions. But we did very well until 1951, and we still do better now than we could have before.
So, thank goodness for Ft. Sumter, and the CSA state surviving for 50 years--because without it, I doubt we would be as great a nation as we are today.