There's a theory that I can't recall the name of right now that says political leanings natural coalesce around 2 "parties" regardless of how many there are muc

There's a theory that I can't recall the name of right now that says political leanings natural coalesce around 2 "parties" regardless of how many there are much less none at all. It makes sense really. Voting on something is a binary action so logically groups coalesce around for or against.