Illinois state Sen. Dave Koehler, who abruptly exited the Democratic primary in the 17th Congressional District race two weeks ago, shed some light Thursday on his surprising decision. He said he dropped out the same day U.S. Sen. Dick Durbin, D-Ill., told him he was going to endorse rival Cheri Bustos. Koehler’s exit came on a Friday, just three days before the filing deadline for state legislative races. Over that weekend, he and supporters had to scramble to get enough signatures to get on the ballot to run for re-election to his state Senate seat. At the time, Koehler said...