The rise of populism concerns many political scientists and practitioners, yet the detection of its underlying language remains fragmentary. This paper aims to provide a reliable, valid, and scalable approach to measure populist rhetoric. For that purpose, we created an annotated dataset based on parliamentary speeches of the German Bundestag (2013–2021). Following the ideational definition of populism, we label moralizing references to “the virtuous people” or “the corrupt elite” as core dimensions of populist language. To identify, in addition, how the thin ideology of populism is “thickened,” we annotate how populist statements are attached to left-wing or right-wing host ideologies. We then train a transformer-based model (PopBERT) as a multilabel classifier to detect and quantify each dimension. A battery of validation checks reveals that the model has a strong predictive accuracy, provides high qualitative face validity, matches party rankings of expert surveys, and detects out-of-sample text snippets correctly. PopBERT enables dynamic analyses of how German-speaking politicians and parties use populist language as a strategic device. Furthermore, the annotator-level data may also be applied in cross-domain applications or to develop related classifiers.

While there is literature on ‘populist securitisation’ and on the ‘securitisation of Islam’, the possibility that some populists may desecuritise Islam is not sufficiently explored. Left-wing populist parties have demonstrated solidarity towards Muslim minorities in Europe through a discourse based on inclusionary rhetoric and deconstruction of the securitising narratives promoted by mainstream and populist right-wing parties. However, their attitude towards Islam can be ambiguous. This paper argues that left-wing populists tend to desecuritise Islam. However, desecuritisation happens in ways that do not always accommodate Muslims’ religious freedoms. This happens because the driver of the left-wing populist desecuritisation of Islam lies in the left-wing thick ideology surrounding populism and not in the populist thin core. I illustrate this argument through the case study of Jean-Luc Mélenchon, leader of the left-wing populist party La France Insoumise. Through a discourse analysis of texts from 2009 to 2022, I show that Mélenchon has predominantly desecuritised Islam. While his desecuritisation is populist, it has not been truly emancipatory for Muslims. Although a more committed fight against Islamophobia has emerged since 2019, Mélenchon’s ideological attachment to laïcité hinders a full rearticulation of French political community based on genuine recognition of Muslims’ religious freedoms.

In this article, we explore the consequences of the increasing presence of both left- and right-wing populist parties in government, critically reflecting on the recent scholarship on the topic, underlining promising venues for future research and outlining a conceptual framework which constitutes the background of this special issue entitled ‘Populism in Power and its Consequences’. Our main contribution is empirical, since – by reflecting on the various articles hosted in the special issue – we assess the impact of populist parties in government on politics, polities and various policy domains. We also provide an account of potential moderating factors of the influence of populists in government, focus on different ideological underpinnings of types of populisms (left-wing and right-wing) and discuss their relevance. We conclude by identifying four possible scenarios for European populist parties in governments: radicalization, compromise and moderation, splintering, or loss.