Complex sentence: Dahlman was elected mayor that year, and in eight out of nine subsequent campaigns for mayor between 1906 and 1930; it was in the one election Dahlman lost in 1918 set the stage for racial violence in Omaha.
Split into simpler sentences: Dahlman was elected mayor that year, and in eight out of nine subsequent campaigns for mayor between 1906 and 1930. The one election Dahlman lost in 1918 set the stage for racial violence in Omaha.