Every period of history, and indeed every event, is both entirely unique and simultaneously a carbon copy of some earlier model. At the moment, the British party system is in disarray; a new insurgent populist movement is capturing the energy of a great body of citizens who feel that the United Kingdom as now constituted doesn’t work for them and doesn’t represent their interests. Almost every commentator with a smattering of British political history under their belt is drawing parallels to the last great party shift in British history: the collapse of the Liberals and the rise of Labour,...