Volatile campaigns? The effects of shocks on campaign effectiveness in British general elections

Some political events, such as the referendum on the UK's continued membership of the EU in 2016, have the potential to alter substantially the electoral landscape, changing long-standing patterns of party alignment and support. Recent work suggests they also have the capacity to influence where and how much parties' local campaign efforts might affect their support. Analysis of the fallout from the UK's Brexit referendum suggests that after the vote, pro-Brexit parties' campaigns yielded greater rewards the lower the local support for Brexit, while pro-Brexit parties' campaigns became more effective where support for Brexit was higher. In this paper, we subject that claim to further scrutiny. Firstly, we employ alternative measures of campaign intensity with greater coverage of cases to assess whether the findings hold. Secondly, we broaden our understanding by looking at the campaigns of a wider range of parties than in the previous research. Thirdly, we extend the analysis to examine another political shock with major electoral consequences, the 2014 referendum on Scottish independence. Our results broadly confirm previous research findings, but we also uncover some important variations and differences. Parties do not campaign in a vacuum: no matter how professional their operations, the climate of national and local opinion affects their capacity to gain a hearing.