You are using an out of date browser. It may not display this or other websites correctly. You should upgrade or use an alternative browser.
alternatehistory.com
The challenge is to create a situation where the US is at some stage involved in something closely resembly OTL's WW1 and where opposition is strong enough that, following an election between 1912 and 1924 the US leaves the war.
Obviously this challenge does allow you to somewhat change the dates of WW1 and although this is in the post 1900 forum you are allowed to have pods back to say 1890.