Responding to populist challengers: The electoral impact of discursive issue-based and non-issue-based strategies in the European Parliament

When dealing with radical and populist parties on either side of the political spectrum, other parties have various discursive strategies at their disposal in order to counter any electoral losses they experienced or might fear in the future. Firstly, parties can alter their issue profile to increase salience of issues that the challenger has brought forward, thus affect their own issue ownership and ultimately electoral success. Secondly, they can also resort to non-issue-based strategies aimed at isolating the challenger, which can further hurt the challenger electorally and subsequently benefit others. While the latter strategies, sometimes called "cordon sanitaire", are often understood as formally excluding challengers from offices and prestigious roles in parliament, it can also mean refusing to communicate with each other or even abstaining from referencing to them. Rather than understanding the "cordon sanitaire" as a formal exclusion, it therefore can take the form of discursive (non)interaction. Thus, instead of formal ex- or inclusion of the party from important roles, I focus on the extent to which party members are or are not interacting with and referencing challenger parties from the radical and populist left and right on Twitter. This discursive non-issue-based strategy may be used in combination with or apart from increasing salience of issues that are owned by the populist challenger. In contrast to other studies, that have looked at the impact of both issue-based and non-issue-based strategies, I argue that both strategies can be identified simultaneously in the Twitter discourse during the legislative period. What further sets my study apart from others is that I do not focus on a single issue such as migration but take into account the multi-dimensional nature of issue competition. A Structural Topic Model is employed to determine politicians' communicative issue-based behavior from their direct communications in the 8th European Parliament (EP) and to explore empirically the issues the challengers on the populist left and right occupy. The EP is a so far less researched case, as well as exploring the impact of populist radical challengers from both sides of the political spectrum on other parties in the party system. To show the effect of parties' use of both issue-based and non-issue-based discursive strategies towards populist challengers on electoral success in the 2019 EP election, regression models are employed. Additionally, the different impact of ideological proximity towards challengers on the populist left and right on these strategies is taken into account.