Political parties are taken for granted today, but how was the idea of party viewed in the eighteenth century, when core components of modern, representative politics were trialled? From Bolingbroke to Burke, political thinkers regarded party as a fundamental concept of politics, especially in the parliamentary system of Great Britain. The paradox of party was best formulated by David Hume: while parties often threatened the total dissolution of the government, they were also the source of life and vigour in modern politics. In the eighteenth century, party was usually understood as a set of flexible and evolving principles, associated with names and traditions, which categorised and managed political actors, voters, and commentators. Max Skjonsberg thus demonstrates that the idea of party as ideological unity is not purely a nineteenth- or twentieth-century phenomenon but can be traced to the eighteenth century.