As thousands of migrants continue to arrive in Illinois, securing the nation’s border is front and center in one congressional race. During the March 19 primary, Republican voters will be choosing between Mike Bost, R-Murphysboro, who has represented the 12th Congressional District since 2015, or former state legislator Darren Bailey, R-Xenia. The district covers 34 southern Illinois counties, including Metro East, and stretches from Charleston to Cairo.