Abstract
The paper sets out three models of the influence of populist attitudes on voting 1.The sole reason for voting for populist parties. 2. A major influence competing with other influences. 3. No significant influence because widely diffused in the electorate. The lower the percentage holding an attitude, e.g. extreme right or left wing ideology, the fewer votes it can affect. . The more widespread, e.g. concern with immigration, the more widely diffused among all parties. It distinguishes populist parties from a larger universe of Outsider parties never responsible for government and seeking support on personal, ethnic and environmental grounds. The impact of populist parties on government depends not on their size but whether the seats they win in Parliament are critical for forming a government coalition and whether mainstream parties treat them as pariahs or partners.
