While the issue of contestational politics has received increasing scholarly attention over the past decades, the study of backlash politics in the legislative process has been studied to a much lesser extent. Departing from a conceptualisation of backlash politics that stresses the importance of the use of retrograde-oriented tools and extraordinary practices (Alter & Zürn, 2020), this article inquires in the study of derogation processes in the regional and national chambers of Spain using an original database containing all the bills passed between 1980 and 2021. We argue that longer single-party tenures, incumbent practices of turning a blind eye to consensus building and systematic vetoes to executive bills by the opposition increase the chances of backlash, even after controlling by the effective number of parties and party ideology. The results suggest that legislative backlash can only be explained by looking both at the governing parties and at the opposition, and that any ‘solution’ to such form of contestational politics is only possible by addressing both sides of the equation.