The Republican Governor is unpopular, Senator Kirk is way down in the polls and will lose big.
... There's a huge divide between Chicagoland and the rest of Illinois. Chicagoland is about as liberal as Boston; the rest of Illinois is to the right of Indiana in its voting patterns. Governor Rauner is still underwater in downstate Illinois; Governor of Illinois must be one of the most snake-bitten political assignments possible.
Donald Trump is down almost 67-19 in Chicago, and 56-25 in suburban Chicago. Downstate Illinois? Trump is up 40-39 with 15% undecided. Ouch!
Senator Kirk actually has a significant lead in downstate Illinois (45-36); he is losing by about a 61-26 margin in Chicago itself and 52-31 in the suburbs.
A quick lesson on Illinois geography: outside of Chicagoland, Illinois is very rural -- more rural than Indiana as a whole. The divide may be along the line of whether one is a member of a farm or pays a big chunk of one's income as rent to what looks like a passive investor.
Has the NRSC cut the cord on Kirk yet? I know they gave up on Ron Johnson in Wisconsin