It’s going to get ugly, but don’t you dare look away.

The upcoming Illinois governor’s race between Pat Quinn and Bruce Rauner may go down as the most brutal in the state’s history.

And I’m not talking about the campaign ads, which everyone has already come to expect will only get progressively worse from one election to the next.

This election is going to be worse because it’s going to get personal, and not just between the candidates.

Before it’s over, regular people are going to see that this race hits them where they live, either directly or by impacting their belief system, much as in a presidential campaign.

Many already have chosen sides, me included.

Mark my words: Long before November rolls around, you are not going to want to talk Illinois gubernatorial politics in a social setting unless you are prepared to deal with some strong opinions.

I predict two competing crusades will emerge, each righteous in its faith in its cause, if not necessarily in its candidate.

In making his Republican primary campaign into an assault on public employee unions and “union bosses,” Rauner has turned this into a life-and-death struggle for organized labor and the working men and women it represents.

By necessity, stopping Rauner will have to become a crusade for the unions, no matter their dissatisfaction with Quinn over cutting into their pensions — or they must be prepared to suffer the consequences.

In turn, they are going to have to help Quinn make the case that what’s at stake reaches beyond the union membership to the workers’ rights and protections they helped carve into law over decades.

Likewise, ousting Quinn from power has taken on a crusade-like aura of its own for those who equate the Illinois Democratic Party with public corruption and blame it for the state’s poor business climate. Frustrated that they can’t get a direct vote on the fate of House Speaker Mike Madigan — or another shot at President Barack Obama — they see dumping Quinn as the next best thing.

In Rauner they believe they have their champion, a candidate who can make good on his pledge to “shake up Springfield to bring back Illinois.”

They are the ones who agree when Rauner says “we all agree Pat Quinn is a failure as governor,” and they will treat any defense of Quinn as a defense of the status quo, which admittedly is an awkward place to make a stand given the state’s obvious economic problems.

Yet that’s where I find myself, more comfortable with the devil I know than the devil I’m still trying to unravel.

As this campaign evolves, we’re probably going to see most small business owners staunchly on one side of this divide and most public schoolteachers on the other.

The small business owners believe Rauner will restore prosperity by making the state more attractive to business, growing the economy in the process. Exactly how he plans to do this remains to be seen. Rauner has suggested one way will be to cut taxes, but he has been short on details.

The teachers may believe Quinn double-crossed them on their pensions, but they will come to understand, if they haven’t already, that Rauner is someone who fundamentally favors limiting their collective bargaining rights.

I asked Rauner earlier in the campaign if he believed teachers should have the right to strike. He said: “Ummm …” And then he said he’d get back to me later. I’m still waiting.

I mention that as an example to illustrate that nobody knows what they don’t know about Rauner. He’s come from off the political map and used his vast resources to shape an image for himself that he believes can get him elected. Even his business record remains a mystery, most voters having little knowledge of what it really means to be a venture capitalist.

Conversely, I’m well aware of Quinn’s shortcomings. That’s because he’s been in the public eye such a long time. All of us have had the opportunity to take the measure of the man. We know his strengths and weaknesses, although I don’t doubt that before Rauner’s opposition researchers are finished we will learn more about the weaknesses.

My take on Rauner is that he brings an owner’s mentality to politics. The State of Illinois is his next acquisition. He’s a goal-oriented man who has switched his sights from making money to acquiring power. He’s paid no dues but now is well on his way to buying an election.

Like I say, everyone is going to have a strong opinion before this one is over. I’m just letting you know where I stand from the start.

Email: markbrown@suntimes.com

Twitter: @MarkBrownCST