The Politics of Disinformation Accusations: A Computational Text Analysis of Political Lying Accusations in the European Parliament

Accusations of political lying have become ubiquitous in contemporary democratic discourse. Despite widespread claims that we live in an era of 'post-truth' politics, we lack systematic evidence about which political actors are accused of lying and, crucially, who makes these accusations. Existing research has focused on isolated instances of deception or relied on anecdotal evidence, leaving fundamental questions unanswered about the relational dynamics of lying accusations in parliamentary politics. This paper asks: Which political actors are accused of political lying, and who are the accusers? We adopt a novel relational approach that examines not just targets or sources in isolation, but the dyadic relationships between accusers and the accused. We analyze parliamentary debates from the European Parliament using advanced natural language processing (NLP) techniques to systematically identify lying accusations over time. We integrate insights from research on populism and negative campaigning to advance competing hypotheses. Regarding targets, we expect MEPs from populist and governing parties to be disproportionately accused, as their prominence and norm-breaking rhetoric make them attractive targets. Regarding sources, we hypothesize that MEPs from populist, ideologically extreme, and opposition parties are most likely to make accusations, using them strategically to discredit mainstream "elite" politicians. Our relational approach further tests whether ideological distance and electoral asymmetries between party pairs predict accusation patterns. We employ multilevel regression models analyzing party-year and dyadic party-pair data, incorporating party characteristics from established datasets (V-Party, ParlGov) measuring populism, ideology, governing status, and electoral performance. Understanding the structural patterns of lying accusations is crucial for broader debates about disinformation and post-truth politics. By revealing which actors dominate discourses of political deception, this research illuminates how accusations of dishonesty have become embedded in routine parliamentary behavior. These findings provide essential groundwork for understanding whether lying accusations reflect underlying patterns of political polarization and partisan conflict in contemporary European democracy.