This article focuses on three mechanisms to explain the rise of populist movements across Europe. They are politicization of resentment, exploitation of social cleavages, and polarization of resentment and feelings of non-representation. We conceptualize populism as a strategic power game aiming to transform potential majorities into real ones by creating or reframing social cleavages. Our theoretical model is used to explain the rise of the Five Star Movement (M5S). Beppe Grillo's M5S gained notoriety on the national political scene in Italy just before the 2013 elections and succeeded in getting nearly 25 percent of the overall vote. Moreover, it was the only political force that was able to attract votes across the different regions in Italy, making it the country's only truly national party.