Abstract
<jats:p>This paper studies how elections shape political communication. We formulate a theory of electoral competition with costly communication. If opposite candidates reach different audiences with their messages, they diverge and seek to polarize the electorate. We then analyze Twitter/X communication by 367 political leaders in 21 countries during 2013-2022, focusing on competition between populists and non-populists. Following Gentzkow, Shapiro and Taddy (2019), we estimate a structural model of speech and show that political rhetoric becomes more polarized before the election. This reflects two main theoretical mechanisms: politicians increasingly emphasize issues distinctive of their type, and within each issue, they use more extreme language.</jats:p>