alternatehistory.com

The challenge is to change the result of the losing party's primary in a US presidential election, and have that party win. Both the primary change and general election must be relatively plausible. You cant stop third party runs like 1912, but in that case you could have Teddy win the primary. The unwritten rule against challenging incumbents may be plausibly broken. All elections from 1900 to 2012 are acceptable. 1964 may be a good place to start.
Top