Even as he struggles to unite his Republican Party, Gov. Bruce Rauner says the state's political parties are becoming dominated by its "extreme elements," and offered as proof the primary challenges he has faced, including one motivated by an angry GOP base constituency of social conservatives.

In a largely overlooked speech to the Illinois Chamber of Commerce last week before the first televised debate of the fall gubernatorial campaign, Rauner dubbed himself a centrist seeking "moderation" as he blamed the partisan drawing of political boundaries for helping fuel political divisions in the state and country with a "devastating" result.

"I believe one of the reasons we have such vicious partisan disagreements and vitriol in America today is that the gerrymandering process has been carried out in most states in America to such a degree that each political party is more and more dominated by its most extreme elements," Rauner said Thursday, hours before his first debate with Democratic rival J.B. Pritzker and two third-party candidates.

"And boy, it's happening in Illinois. I've lived it through my two primaries I've had in my time in public service and I've seen it in both political parties in the state of Illinois. And for America to function effectively as a democracy, we can't go to the most extreme elements of each of our political parties. It won't work. It will not work well," he said.

Rauner faced an unusually strong challenge in the March Republican primary from state Rep. Jeanne Ives of Wheaton, winning by 3 percentage points. Ives capitalized on the discomfort of social conservatives over his signing into law legislation expanding abortion, immigration and transgender rights.

Republican state Rep. Sam McCann of Plainview is attempting to capture the discontent of social conservatives in his Conservative Party candidacy for governor. Rauner has called his candidacy "phony."

Since the primary, Rauner has worked to rally the GOP around his general election campaign. He has focused a great deal of time campaigning in less-populated rural Downstate areas dominated by socially conservative Republicans, including a visit Monday to the southeastern Illinois community of Hartford, with a population of under 1,500 people near the mouth of the Missouri River.

But as he criticized the intraparty challenges he has faced as representing "extreme elements" in the GOP, Rauner also told the business group of the difficulty he has had in being a centrist.

"And boy, I've got to tell you, holding the center, holding the center has been incredibly hard here as governor. Done my darnedest. Held it as firmly as I can. But holding the center in today's American politics and in Illinois' politics — tremendously difficult. But we'll stay the course," Rauner told the state chamber, which has backed his re-election.

"We'll stay strong, stick to what I firmly believe is right and that's fiscal discipline, pro-free enterprise, pro-growth, pro-taxpayer, pro-job creator and moderation in other regards, finding the center," he said. "Moderation is the right answer and I will stay there. I believe that's the way Illinois can be saved and we can create a better future."

While criticizing political divides, Rauner has used his time Downstate regularly using the rhetoric of regional politics by attacking Chicago and its "corrupt" Democratic political machine.

Yet, he told the group, "I firmly believe we're coming together as a state. I feel it every day as I travel the state."

The first-term governor also twice asked the state's business leaders to invite him to come to their facilities to help his re-election.

"We can't let anybody stay home. And my offer to you is I will come to any city, any municipality, any county, anytime, any company in the state of Illinois, if you'd like to do (an) employee town hall, like to do a meeting with any of your executives, a meeting with your factory floor workers," he said. "Anywhere, anytime."