I've exhausted all my google-fu over this one.
- Short story published during the golden age of sci fi
- (Probably) published in either Fantastic Science Fiction or Galaxy Science Fiction
- Dialogue is retrospective, explaining all this sequentially except for the begin
- Setting: 'Modern day' (1950s?) United States .
- Lead character is a university professor at a US university or college
- For some unknown reason, people start quarreling and rioting over a seemingly random or arbitrary phrase ("X beats the Y" vs "Y beats the X" or something?)
- Order of words determines what "side" you're on.
- Abrupt personal violence breaks out between opposing sides
- Lead character comments about the news to wife, divorces him without explaining what the phrases mean "I thought you of all people would understand, [name]."
- Society collapses and the US is divided in two camps, east and west coast.
- Lead character is absolutely clueless and eventually finds his way to the rocky mountains or other forest/wilderness without explaining how, as the story is retrospective.
- One side was eventually shortened to be call the "Pennys" by the lead character. Or maybe some other short word.
- both sides have eventually wore colored clothing to identify itself, green shirts or something?
That's all information I got. And I still can't find it.