Plot synopsis: The USA is in the grips of a rancorous partisanship the like of which has not been seen in nearly a century. Every political issue today invariably becomes a pitched partisan battle, irrespective of the issue - be it the economy, global climate change, education or foreign policy. The two parties are further apart than they have been in generations and this extreme polarization has made it nearly impossible to govern the country effectively. How has the United States become so divided? SPLIT journeys from coast to coast to find an answer to that question at a time when it is needed most.