The Republican and Democratic Parties can seem like permanent institutions, but their agendas today bear little resemblance to what they once stood for. Political parties have repeatedly died out in American politics, often after periods of instability and infighting. [Jelani Cobb](https://www.newyorker.com/contributors/jelani-cobb) joins Dorothy Wickenden to discuss how drastically the two major parties have changed over time, and whether Trumpism has wrecked the G.O.P.