Earlier research covers extensively the content of messages used by political parties in election campaigns. Although ultimately resulting in a vote, referendum campaigns allow for more policy-oriented messages and make room for messages that do not always fit elections. At the same time, messages run across political parties, addressing broader segments of issues. So far, little attention has been paid to the content of messages in referendum campaigns. It remains unclear what are the issues emphasized and how political parties decide on these. This paper seeks to fill this gap in the literature by proposing and testing a theoretical framework that can pave the way to further analyses on the topic. Data on 38 referendums across 15 countries from 2015 to 2020 were gathered through both quantitative and qualitative methods. This paper tests six variables from the framework; issue ownership, issue salience, incumbency, ideological consistency, coalitions, and pressure groups.
