Over a century after Robert Michels (1876–1936) published his lengthy treatise Political Parties, the book is still in print in multiple languages and is still studied and frequently cited. In his most influential work, Michels famously demonstrated the “iron law of oligarchy” that affects even avowedly democratic political parties, taking as his case study the world’s first million-strong socialist party, the German Social Democrats (SPD). The critique Michels put forward benefited from his close knowledge of the party and its literature — he had been an active member of the SPD from 1902 to 1907.

Much of what Michels argued in 1910–11 rings true today. There is at least a tendency for large political parties to become dominated by the cadres of professional functionaries that grow up within their structures. Ordinary workers who make the transition to full-time political professionals typically cease to be working class and become something else. The party furnishes social mobility and relative affluence for a stratum of political representatives and paid officials, even as it fails to transform the hierarchies of the wider society. Rank-and-file members are unable or unwilling to challenge their leaders, even if they sometimes disagree with them.

Critics of contemporary progressive parties still cite Michels — and if they don’t, they certainly could. Consider the criticisms that have been leveled at machine politics from the creation of “Tammany Hall” in the nineteenth century to the role of the Democratic National Committee in the era of the Clintons and beyond. Or consider the overtly manipulative rule of the UK’s New Labour elite under Tony Blair and certain of his successors, with their phalanx of advisers and spin doctors.