The spatial diffusion of party entrepreneurs in Swedish local politics Gissur O ´ . Erlingsson a,b, * a Vaxjo School of Social Sciences, Va ¨xjo ¨ University, Political Science, Georg Luckligs vag 8, 351 95 Vaxjo, Sweden b The Ratio Institute, Stockholm, Sweden Abstract Theoretical expectations predict instances of party formation to be unusual. It is therefore puzzling that new ‘non-national’ parties became increasingly common in Swedish local councils between 1973 and 2002. This article sets out to answer why party formation became an increasingly popular strategy throughout these years. I show that previous research has not provided satisfactory answers, and argue that existing theories are of limited use explaining this development. It is suggested that a diffusion mechanism may explain why new parties became increasingly common in Swedish local councils. Theoretically, it is argued that an entrepreneur who creates a new party inspires potential entrepreneurs in neighboring municipalities to repeat this at later points in time. A geographical clustering of municipalities where these parties exist is therefore expected. Support is found for this assertion. The result is important since it outperforms the alternative ‘local contextual’, socioeconomic hypotheses previously tested in this empirical setting. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Party entrepreneurs; Spatial diffusion; New parties; Imitation; Local politics; Sweden Introduction New political parties are not expected to materialize that easily. As Olson (1971: 15) pointed out, the provision of public goods is the function of organizations generally. Since political * Vaxjo School of Social Sciences, Va ¨xjo ¨ University, Political Science, Georg Luckligs vag 8, 351 95 Vaxjo, Sweden. Tel.: þ46 76 88 23 310. E-mail address: gissur.erlingsson@vxu.se 0962-6298/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.polgeo.2008.11.003 Political Geography 27 (2008) 857e874 www.elsevier.com/locate/polgeo