The latest battle between organized labor and states trying to fix huge budget problems by cutting pension costs has surfaced in Illinois, where public union leaders are waging an all-out effort to stop the Democrat-led campaign.

Details of a plan reached last week appear to show state legislative leaders are attempting to solve Illinois' $100 billion pension crisis in part by changing workers' retirement age, reducing automatic pension increases and limiting their collective-bargaining privileges.

Union leaders argue the plan to help the under-funded pension plan, which appears to have bipartisan support, seems no different than the one the General Assembly rejected earlier this year.

“It’s an unfair, unconstitutional scheme that undermines retirement security,” the We Are One Illinois labor coalition said last week as details of the plan emerged. "It’s no compromise at all with those who earned and paid for their retirement benefits. In fact, reports suggest the leaders have repackaged Senate Bill 1 and barely bothered to disguise it.”

Rank-and-file state lawmakers were briefed on the plan Friday, and a vote could come as early as this week.

Leaders of the unions, a usually reliable Democratic vote, are specifically targeting Democratic state senators from moderate, swing districts where election opponents can hammer them for inaction or being too tough on state workers and say eight to 10 of them are considered "persuadable."

The battle is the most recent to play out across the Midwest where Republican governors in Wisconsin, Ohio and Michigan have worked to limit collective bargain deals to reduce budget shortfalls.

The most epic battle took place in Wisconsin in 2011 when GOP Gov. Scott Walker led an effort to get the General Assembly to pass legislation that limited collective bargaining for most state workers and required them to pay more for their pensions and health-care benefits to help reduce a projected  $137 million budget shortfall.

The move sparked weeks of protests in the state capitol, a national debate on the issue and a failed attempt to recall Walker, who was faced with a projected $3.6 billion deficit when he signed the legislation.

Illinois Democratic Gov. Pat Quinn and the four legislative leaders of the Democrat-controlled Assembly say the plan will save the state an estimated $160 billion over 30 years and are working to secure enough support for passage.

The Associated Press contributed to this report.