(iPoster) Mechanisms of Cross-Border Diffusion of Right-Wing Populism

• In Event: Poster Session: International Political Economy I & Perspectives on Canadian Foreign Policy
  In Poster Session: Poster Session: International Political Economy I

Abstract

The rise of right-wing populism in Western democracies has become a central topic in political science over the last decade. Populist leaders not only gain increasing support domestically but also reinforce one another internationally, highlighting their collective challenge to the liberal international order and underscoring the contagious nature of populism. Nevertheless, However, existing empirical studies often give limited attention to the diffusion of populism, treating its rise as parallel developments across countries. This paper, in contrast, focuses on how the electoral success of right-wing populist leaders in one country actively influences the trajectory of populism in others, offering novel perspectives on the mechanisms of cross-border populist diffusion.

I hypothesize that populist diffusion occurs through three main channels. First, the success of populist leaders legitimizes extreme ideas and shifts social norms, making populist rhetoric more attractive to foreign voters. Second, the electoral victories of right-wing populists draw foreign voters' attention to issues where populists hold a comparative advantage over mainstream parties, thereby reshaping the political agenda in other countries to align with populist priorities. Third, populist successes increase the visibility and perceived viability of similar movements abroad, making it easier for far-right parties in other countries to engage voters and enter the political mainstream.
To test these hypotheses, I use Donald Trump’s unexpected victory in the 2016 U.S. presidential election as an exogenous shock to European politics. Employing a differences-in-differences design, I examine the effect of Trump’s election on the salience of the immigration issue, which is always emphasized by right-wing populists, the visibility of far-right parties, and voters’ anti-immigration attitudes in European countries.

The analysis reveals three key findings. First, Trump’s election caused a sharp increase in the salience of the immigration issue in European countries. Google Trends data show a surge in searches related to immigration immediately after the election, reflecting how populist success can elevate specific issues abroad. Second, the Google search interests of far-right parties also increased significantly in Europe, suggesting that populist victories abroad enhance the prominence and perceived potential of ideologically aligned movements. These results on issue salience and party visibility are further corroborated by a case study of British media coverage. Lastly, data from the European Social Survey indicate that Trump’s election polarized public attitudes toward immigration. Anti-immigration sentiments rose among voters dissatisfied with the political system, while other voters’ attitudes remained stable.

This paper makes two key contributions. First, it directly tests the process of populist diffusion, focusing on how the success of populist leaders in one country influences political dynamics in others. Second, while previous studies on the diffusion of ideas have emphasized the shift in voter preferences as the primary channel of diffusion, this paper expands the focus to include other crucial mechanisms—such as the shift in issue salience and the visibility of similar parties. By doing so, it offers a more comprehensive understanding of how populism spreads across borders and reshapes political landscapes internationally.

Author

• Xiuyu Li, New York University