77

This study analyzes the diffusion of far-right ideas in the general policy statements of French Prime Ministers (1959–2024) using Natural Language Processing (NLP) methods. It develops and introduces the Far-Right Ideological Score (SIED, for score idéologique d’extrême droite), a quantitative indicator designed to measure the proportion of far-right ideas within political discourse. The results highlight three significant periods: a peak during the Algerian War (1959–1961), a decline following May 1968, and a steady rise from the 1970s onward, intensifying after 2005 in particular. The study reveals a cross-party diffusion of far-right ideas, particularly driven by centrist and right-wing forces. The concepts of co-optation and metapolitics are used to interpret these findings.