The challenge here is to created a scenario that leads to a world war that last for more then 20 years, Your POD most be after 1800
He might have meant 1900 hundred but pressed the wrong button.Shouldn't this be in Pre-1900?
Too easy,Easy.
Cold War (which was anything but cold)
An interesting idea, but the chances of the U.S. supporting a communist regime, especially in the early 20's are close enough to zero to approach unity.Too easy,
Here is another, US not involved in WW1, French defeat in 1919, Britain stays in and attack Norway to cut off iron in 1920 while fighting defensivelyv from Italy. US becomes gradually more sympathetic and the new USSR comes back in in 1921 with us supplies.
Germany is restocked with ukrainian grain and hangs in there, Germany now attempts to knock out Britain with unrestricted submarine warfare drawing in the us fully. Building up for new offenses takes years and involves a Balkan detour gradually Breaking AH and an invasion in France occurs in 1924. Unfortunately, while making a strong normandy bridgehead, the USSR now collapses leading to a gradual overwhelming of the bridgehead which is evacuated in 1925. Germany mops op the Balkan with AH in 1926-7 eventually, trying to Strange Italy in 1927-28. Peace conference follows.
14 years. Add some more stalemates and we are getting somewhere
Easy.
Cold War (which was anything but cold)
Editing now, wait 5 mins. USSR recovery faster ITTL without the whites and civil war shorterAn interesting idea, but the chances of the U.S. supporting a communist regime, especially in the early 20's are close enough to zero to approach unity.