What has caused the marked, cross-national, and unprecedented trends in European electoral results in the 21st century? Scholarly explanations include social structure and challenger party entrepreneurship. We argue that these electoral changes more proximally result from public issue salience, which results from societal trends and mainly affects rather than is caused by party agenda setting. We use aggregate-level panel data across 28 European countries to show that the public issue salience of three issues—unemployment, immigration, and the environment—is associated with later variation in the results of the conservative, social democrat, liberal, radical right, radical left, and green party families in theoretically expected directions, while the party system issue agenda has weaker associations. Public issue salience, in turn, is rooted in societal trends (unemployment rates, immigration rates and temperature anomalies), and, in some cases, party agenda setting. We validate our mechanism at the individual-level across 28 European countries and using UK panel data. Our findings have implications for our understanding of the agency of parties, the permanency of recent electoral changes, and how voters reconcile their social and political worlds.