They hold a quarter of seats in cantonal parliaments , but are the largest party in only one : Basel - Stadt ( coloured red above ) .
Strongest in urban areas , the Social Democrats ' support is spread across the country .
Social Democrats hold a quarter of seats in cantonal parliaments , but are the largest party in only one : Basel - Stadt ( coloured red above ) .
Strongest in urban areas , the Social Democrats ' support is spread across the country .