Georgia’s unique runoff system shaped by long, complicated history

Georgians sifting through piles of campaign mail mixed in with their holiday cards can blame the state’s unique runoff system, which has survived multiple legal and political challenges since it originated more than 100 years ago.

Georgia is one of 10 states, mainly in the deep South, that require a runoff if no candidate receives a majority of the votes cast in a primary election. But Georgia is alone in mandating runoffs in general elections, which is how the state is hosting two Senate contests on Jan. 5 that will...