Some labor experts say it makes sense for the unions to join forces.

"They're more likely to be effective if they can speak in a united front. It doesn't always happen," said Robert Bruno, a professor of labor studies at the University of Illinois. "I suspect it will be noticed in Springfield."

The coalition's materials emphasize that many public employees — the group says 80 percent — are not eligible for Social Security. That means they rely more heavily on their pensions than most other retirees.

The group also points out that employees contribute money to their retirement funds as required, but state government has often skimped on its contributions.

"I did my job, but they want to take my pension because the politicians didn't do theirs. Anyone who thinks that's right should take a walk in my shoes," says a coalition ad portraying a police officer, a teacher and a firefighter.

Illinois has struggled with a budget deficit for years, leading officials to raise income taxes and cut spending in some areas. But the gap remains at about $8 billion.

Looking for new places to cut, some officials point to retirement costs. They suggest making retirees pay more for health care or contribute more to pension funds. There are calls to cut pension benefits, although the state Constitution appears to prohibit that.

It's not just Republican-leaning states like Indiana and Wisconsin that have cut union benefits and bargaining powers. Bruno noted that Massachusetts, a Democratic state like Illinois, has done the same.

While unions are a frequent target of criticism, their public relations efforts could pay off, said Martin Malin, head of the Institute for Law and the Workplace at Chicago-Kent College of Law.

"It's an attempt to influence the political climate and I certainly understand why they're doing it, given the onslaught of opinion going the other way," Malin said.