Generally speaking, it is believed that the Narodnik (People) movement in Russia and the People’s Party in the US, both of which arose in the latter half of 19th century, are the earliest examples of the use of the term “populism.” Ever since then, the term populism has been used to describe movements in many countries in Europe and America as well as in parts of Asia and Africa. Populism is an intermittent movement recurring in different historical periods. The most recognizable is during the 1930s and 1940s, and the latest started at the end of the 20th century, continuing until now. Populism often brings about significant changes, like shifts of governments and institutional reform, as well as conflicts and wars of varying degrees.

During the more than 100 years since the appearance of the term populism, academics in various disciplines like politics, history, philosophy, law, international relations, public policy and media studies have conducted many discussions on theoretical, practical and individual cases of populism. Nevertheless, in terms of a phenomenon that has existed all across the world with direct political and social consequences, it is very hard to clearly understand it from the perspective of a single subject or an individual case. For example, while studying current “right-wing” populism in the US, (although notably some people think that Trump belongs to neither left nor right in the traditional political spectrum,) it is difficult to see its historic roots if only analyzing it from a political perspective. It is also hard to find the nature of populism if only analyzing it on the level of public policy. When we study right-wing populism in Italy, it is hard to see the whole picture without comparing it with populism in France, Spain and Germany. Furthermore, it is even more difficult to accurately understand the universality and heterogeneity of populism if we do not compare it with left-wing populism in Latin America. And if we ask a scholar to conduct comprehensive studies, he might lack the interdisciplinary background to do it.