In this article, I critically engage with the populism literature, and predicated on a conceptualization of modern democracy as a mixed regime (combining oligarchy and democracy), I provide a mechanism to connect populism-in-power to authoritarianism. As such, I elucidate a particular populist path to authoritarianism in a competitive setting by exploring two questions. First, what is the impact of populism-in-power on the modern democratic mixed regime? Second, what is the locus of populism in a modern democratic institutional framework? Utilizing the Turkish and Argentinean cases as illustrative examples of populism-in-power, I conclude that, first, unless a populist vision is accompanied by democratic institutions outside of the spectrum that modern democracy offers, when that vision which sacralizes and singularizes competitive elections becomes preponderant, it will lead to the opposite of its claim of making the people sovereign, and instead will make the rulers sovereign. Second, I argue that although there is no internal contradiction between modern democracy’s liberal or constitutional and democratic elements, there is still a paradox surrounding modern democracy. This paradox is found between the sources of its imaginative appeal and its practice as a mixed regime, and this is where we should place the perennial potential of populism.