A losing gamble. How mainstream parties facilitate anti-immigrant party success

► A tougher position on immigration by mainstream parties helps to legitimize anti-immigrant parties, and benefits them electorally. ► However, in contrast to previous research, we find that it is not the position of the most extreme mainstream party that matters, but rather the mean position of all the mainstream parties. ► We use a pioneering survey of over 10,000 local elected representatives in Sweden to measure sub-national variation in the position on immigration among the political parties.