On the political science shelves of my library, Margaret Canovan’s excellent Populism (1981) has for a long time been rather lonely next to the serried ranks of books on fascism, liberalism, conservatism and other isms. This has begun to change. The section has already been bulked out with new books by Cas Mudde and Jan-Werner Müller, and I now have Wenfang Tang’s Populist Authoritarianism: Chinese Political Culture and Regime Sustainability to ponder too.

One of the many merits of John Judis’s The Populist Explosion is that it covers fully the various 19th-century US precursors of Bernie Sanders and Donald Trump, as well as European populism today in its left- and right-wing incarnations. Experts may object that Judis does not give Guglielmo Giannini’s Fronte dell’Uomo Qualunque (‘Common Man’s Front’) of the 1940s its due, but this is one of the few omissions in the book. Moreover, unlike many experts on populism, Judis does not overload his book with political-science theory. On the whole, he provides fair-minded and balanced accounts of the variants he considers.

Populist movements, not all of which inevitably become parties, are rather like photographs of an extended family in which certain physical traits, such as big ears or a Habsburg jaw, recur. For his understanding of the phenomenon, Judis is much indebted to Ernesto Laclau and Chantal Mouffe, who described how