As danbruc mentions below we also would really like our networks to only ever split into sets such that there is at most one set which could include a leader; otherwise we might have a more durable consensus split.
That said, algebraic structures are a tool for working with consensus problems, but there’s also process. Together we get consensus protocols. So, for example, you could have a healing process step that privileges the larger group and forces a merge even if at some moment you had two candidates that believed they were a valid leader for their own split network view.