Daniel Rickenmann, a Republican businessman, on Tuesday defeated Democratic attorney Tameika Isaac Devine by 4 points to become Columbia's next mayor. A slew of prominent national Democrats, including Obama, Clyburn, and Democratic National Committee chairman Jaime Harrison, backed Devine in the race. The result shows that Democrats' plummeting popularity extends even to areas the party has historically dominated. Obama, who in a Monday audio message urged Columbia voters to "make history again by showing up for Tameika Isaac Devine," won the city's county by 29 points in 2008 and 33 points in 2012. Clyburn, meanwhile, resides in Columbia and has...