As an IL native I can assure you that there are no republicans in IL, only Ds with a different colored shirt. They feed from the same trough.
It was disgusting how the state party leadership avoided Trump like the plague, even after he won the nomination and even after he was elected. I remember when they reopened that steel mill in Granite City. That was a big deal. Trump was there. Rauner couldn’t be bothered to show up. Madison County, where Granite City is, used to be solid Democrat. Now it’s red. There are true Republican voters, especially downstate. Unfortunately, there aren’t enough true Republican politicians.