Sen. Dick Durbin’s (D-Ill.) decision to not seek a sixth term in the Senate is expected to tee up a spirited Democratic primary to replace him in Illinois next year. Durbin, the No. 2 Senate

The decision by Durbin, who is in his fifth Senate term and is the chamber’s No. 2 Democrat, will set off a flurry of activity among a scrum of would-be successors, both Democratic and Republican. But in a state that has grown more solidly Democratic,