The political logic that divides society into two antagonistic camps — a virtuous, homogeneous people and a corrupt, self-serving elite — and holds that politics should express the general will of the former against the latter. Whether this constitutes an ideology at all is disputed: Cas Mudde's influential account calls it a thin-centred ideology that attaches itself to fuller ones, which is why it appears on both left and right without contradiction.
The American People's Party of the 1890s gave the word its name, mobilising indebted farmers against banks, railroads and the gold standard, and finding a voice in William Jennings Bryan's Cross of Gold speech. Latin America produced its most durable variant in Perón's fusion of labour mobilisation, nationalism and personal authority. Post-war European populism has been predominantly of the right, defining the people ethnically and against immigration, while Podemos and Syriza represented a left populism explicitly theorised by Ernesto Laclau, who regarded the construction of a popular subject as the essence of politics rather than a pathology of it.
The most consequential analytic dispute is whether populism is anti-democratic. Jan-Werner Müller argues its defining feature is not anti-elitism but anti-pluralism — the claim to be the sole legitimate representative of a people whose true will cannot be divided — which makes opposition inherently illegitimate and turns electoral defeat into evidence of fraud. Others hold that populist surges are a corrective, symptoms of genuine representative failure, and that treating them as pathology is itself the elite reflex being complained about.
The tradition's recurring difficulty is that the people it invokes has to be bounded by someone, and the boundary is rarely drawn by the people themselves. Its defenders point out that every democratic theory has this problem and that populism at least states it openly.