Sen. Darren Bailey (R-Xenia), left, and Aurora Mayor Richard Irvin, right, appear to be the front runners in the Republican primary. [Blue Room Stream & Ben Szalinski/The Daily Line]

Most Illinois voters will become eligible on Thursday to vote early in the June 28 primary. Some races remain without a clear frontrunner six weeks before the votes will be counted as candidates ramp up spending on advertisements and continue searching for cash.