UPDATED

For decades, the Midwest has been a fortress for the embattled American labor movement. But in recent years, it has turned into something much closer to a battleground.

In Michigan – the cradle of the American auto industry and the powerful labor union United Auto Workers (UAW) – Republican Gov. Rick Snyder successfully passed “right-to-work” legislation that weakened unions by making it illegal for them to automatically charge fees to the workers they represent. Wisconsin Gov. Scott Walker, another Republican, famously presided over the passage of Act 10 in 2011, restricting public workers’ collective bargaining rights. And in Indiana, organized labor continues to fight a prolonged legal battle against the state’s own 2012 right-to-work law.

Now labor unions in Illinois fear they could be next. This year, Democratic Gov. Pat Quinn is squaring off against a Republican challenger who has made opposition to the labor movement into a central plank of his campaign. Bruce Rauner, a venture capitalist, has promised to establish “right-to-work” zones in Illinois if elected and dramatically revise the state’s public employee retirement system. He has launched bromides against “government union bosses” and touted his donations to charter schools. In other words, he’s everything that labor unions in Illinois fear. And he could win.

VIDEO: Take a quick visual tour through US labor movement milestones

“With the type of candidate that Bruce Rauner is, it does present more urgency,” said Bill Looby, campaign manager for the Illinois branch of the labor federation AFL-CIO, when asked to compare this year’s gubernatorial election to previous races. “His clear antagonism toward union members, his lack of either understanding or respect for low-wage workers in certain sectors of the workforce, and his record on outsourcing, it just presents us with what I consider to be a real clear and present danger to the working families of this state.”

To combat that “clear and present danger,” Illinois’ labor movement got off to an uncommonly early start on the campaign. Labor unions such as the Illinois Education Association came out against Rauner during the Republican primary, and began spending money to try and defeat him before he ever reached the general election. When he won anyway, they reportedly gathered with Democratic leaders in the state to plan a “coordinated campaign” against him and in defense of incumbent Gov. Pat Quinn.

The decision to stand fully behind Quinn is especially striking given that organized labor has clashed with the Democratic governor in the past. In December of last year, Quinn approved major pension reform over the strenuous objections of We Are One Illinois, a coalition of labor unions formed to prevent cuts to public worker retirement benefits. The law Quinn signed, which is now being challenged in court, reduced cost of living increases to pension benefits and raised the retirement age for public workers.

Now the same unions that are fighting Quinn’s pension reform law in the courts are standing with the governor because they fear what Rauner would do to the state’s retirement system. The Republican candidate has proposed that the state’s defined-benefit plan be turned into a hybrid model – the main component of the new plan would be a public sector 401(k) system, along with a smaller, “much more affordable” defined benefit alternative. Something similar was recently implemented in Rhode Island, where the left-leaning think tank Economic Policy Institute – which receives some of its funding from organized labor – projected “an average benefit cut of 14% for future full-career employees.”

Pensions are only the half of it, though. Looby also highlighted Rauner’s plan to create local right-to-work districts within the state, describing it as “a backdoor way of making Illinois a right-to-work state.”

“There is the pension issue and there’s a wide array of others where he presents a distinct anti-union – or anti-worker, actually – bent to him,” he said.

Yet despite the labor movement’s efforts, Rauner appears to be the favored candidate in the race. The most recent RealClearPolitics Average has him 7.3% ahead of Quinn, and some polls suggest he has as much as a 13-point advantage. The fact that Illinois still has a significantly worse unemployment rate than the United States as a whole does not appear to be helping the incumbent candidate. Nor does the persistent skepticism of the financial industry, particularly rating agencies. Last week, the credit rating agency Moody’s Investors Service estimated that Illinois has a larger pension debt burden, proportional to revenue, than any other state.

Rauner’s campaign did not return multiple requests for comment, but he has made at least one recent attempt to push back on the notion that he’s anathema for labor unions.

“I believe that collective bargaining is a good thing,” he said during a late August campaign stop. “It’s a fair thing. I don’t want to take away collective bargaining.”

UPDATE: Shortly after this story was published, the Chicago Tribune released a poll showing Quinn ahead by 11 points. The Tribune suggested that this, along with the high proportion of poll respondents who self-identified as Democrats, could indicate that Illinois is “becoming a deeper blue state.” However, various poll trackers – Including HuffPost Pollster, Real Clear Politics, and TPM Poll Tracker – find the poll to be a significant outlier. Another recent poll, sponsored by the Democratic Governors’ Association, also found Quinn ahead, albeit by just 3 points.