The article examines the evolution of ideological and political attitudes, the essential characteristics and instrumental functions of modern populism using the case of the United States of America. It is well known that populism differs from other political movements in its direct appeal to voters / people as an undifferentiated social mass, and thus constitutes an effective means of mobilizing the masses of the population in a protracted crisis of the political system and its institutions. The instrumental effectiveness of populism is often used to regroup social forces necessary for society and to give the entire political system greater elasticity, to increase its responsiveness to the interests of the “street man,” that is, ordinary voter. The ruling groups, especially in the USA, have learned to use populism effectively as a force capable of reducing the intensity of social conflicts, as well as for the integration of the “dissatisfied” into the existing institutions of the state that they themselves need. The first, and very successful, example of this kind was the “new deal” of F.D. Roosevelt, the political result of which was the creation in America of a “middle class society” that was not susceptible to extremes of both the right and the left. At present, the overlapping civilizational “rift” and the political crisis have forced the influential forces of American society to turn again to populism as a proven means of modifying America’s development model and pacifying a significant part of the population of this country. The 2016 presidential election convincingly demonstrated the powerful instrumental capacities of populism, manifested, in particular, in a certain renewal of the US socio-economic policy. Similar processes of regrouping of socio-political forces are to be observed in other “institutionalized democracies” of the West, which allows us to consider the “new” / “national” populism as a relatively stable and long-term phenomenon of socio-political development of the western world.