abstract: We study the dynamic evolution of populism and its welfare consequences, where populism is defined as a platform proposing a mis-specified model of the world, an alternative worldview. Voters’ trust in the political class evolves over time and depends on traditional politicians’ performance once in office. Our goal is to understand the effects of a key behavioral assumption: reduction in voters ’trust increases the probability of voters believing in the alternative worldview proposed by populists. This framework allows us to study when politicians become populists, when voters vote for them, how long populist and their alternative worldviews survive and their long-run effect on voters ’welfare. We show that populists can discipline traditional politicians, which is beneficial, confounding however voters’ learning. Voters’ trust may fall below a threshold generating “populist cycle” in which traditional and populist politicians keep alternating in office forever, and trust in the political class is never restored.