After the Second World War, countries across occupied Europe were faced with the challenge of restoring political stability at home and peace abroad. Although extremist sentiment had not disappeared, moderate elites resolved to choke it off at the source by building robust bureaucratic parties that could incorporate the masses. Christian democratic parties on the right and moderate social democratic parties on the left took power all across the continent, ushering in an unprecedent period of stability. Yet with the economic stagnation of the 1970s, this consensus began to unravel, giving rise to the emergence of populist alternatives. This chapter departs from existing explanations for this turnaround. It shows that the populist strategy was always most effective in the patronage-based party systems of southern Europe. In northwest Europe, in contrast, bureaucratic parties have adapted, substituting professionalized service provision for mass membership and participation.