Replication Data for: Strengthening Mainstream Consensus? The effect of radical right parties on the defense policies of left parties

We study how the electoral success of radical right populist parties (RRPPs) affects established parties’ defence and security policy positions. The electoral breakthrough of RRPPs creates strategic concerns for established left-wing parties due to substantive overlap between their and RRPPs’ defence-sceptical position. We argue that the electoral success of RRPPs encourages left parties to adopt more assertive defence positions to distinguish themselves from RRPPs, thus increasing mainstream consensus on defence policy. Examining 1155 elections in 27 European countries (1990-2021), we test this argument based on a regression discontinuity design around electoral thresholds for obtaining parliamentary seats. We find evidence that, in response to RRPP success, established parties adopt more assertive defence policy positions. The evidence is more tentative, but in some respects consistent with the argument, regarding the \textit{salience} of defence policy. The findings are driven by left-wing parties, which have stronger reasons to change positions than right-wing parties.