structural:reformatting
Right and left-wing

As a result of the various different ideologies with which populism can be paired, the forms that populism can take vary widely. Populism itself cannot be positioned on the left–right political spectrum, and both right and left-wing populisms exist. Populist movements can also mix divisions between left and right, for instance by combining xenophobic attitudes commonly associated with the far-right with redistributive economic policies closer to those of the left.

core consists of four distinct but interrelated concepts:

The ideational definition of populism used by Ben Stanley

The ideologies with which populism can be paired can be contradictory, resulting in different forms of populism that can oppose each other. For instance, in Latin America during the 1990s, populism was often associated with politicians like Peru's Alberto Fujimori who promoted neoliberal economics, while in the 2000s it was instead associated with those like Venezuela's Hugo Chávez who promoted socialist programs. As well as populists of the left and right, populist figures like Italy's Beppe Grillo have been characterised as centrist and liberal, while groups like Turkey's Justice and Development Party have been described as combining populism with Islamism, and India's Bharatiya Janata Party has been seen as mixing populism with Hindu nationalism. Although populists of different ideological traditions can oppose each other, they can also form coalitions, as was seen in the Greek coalition government which brought together the left-wing populist Syriza and the right-wing populist Independent Greeks in 2015.

Adherents of the ideational definition have also drawn a distinction between left and right-wing populists. The latter are presented as juxtaposing "the people" against both "the elite" and an additional group who are also regarded as being separate from "the people" and whom "the elite" is seen to favour, such as immigrants, homosexuals, travellers, or communists. Populist leaders thus "come in many different shades and sizes" but, according to Mudde and Rovira Kaltwasser, share one common element: "a carefully crafted image of the vox populi ". Stanley expressed the view that although there are "certain family resemblances" that can be seen between populist groups and individuals, there was "no coherent tradition" unifying all of them. While many left-wing parties in the early 20th century presented themselves as the vanguard of the proletariat, by the early 21st century left-wing populists were presenting themselves as the "voice of the people" more widely. On the political right, populism is often combined with nationalism, with "the people" and "the nation" becoming fairly interchangeable categories in their discourse, or combined with religion where "the people" are identified based on religion. Some political scientists have also argued that populism can be divided into left-wing inclusionary and right-wing exclusionary forms, though some argue against a dichotomy between inclusionary and exclusionary forms, such as right-wing populists welcoming culturally proximate migrants with transnational solidarity.