As Illinois lawmakers prepare Friday for their final day of the Spring session, the issue most say should be top priority received a blow Thursday evening.

The full state Senate overwhelmingly rejected a pension reform plan supported by the House of Representatives but panned by several labor unions. Just 17 senators, mostly Republicans, voted in favor of the bill.

“How do you breach a contract?” Democratic State Sen. Kwame Raoul asked during a floor debate Thursday evening. “Well, you renege on a promise.”

The majority of senators voting against the bill said it doesn’t meet the standards of Illinois’ constitution. Unions representing state workers had vowed a lawsuit if the bill passed. But those who spoke in favor of the plan stressed the importance of passing a pension reform bill.

“Retirees are worried and they should be that if we don’t take care of this problem, they may go to the mailbox some day and not have a check that they were expecting,” said Republican Senate leader Christine Radogno.

The bill called for a number of changes to employees’ retirement plans, including raising the retirement age and reducing cost of living increases in retirement.

Gov. Pat Quinn condemned the senate’s vote, saying in a statement, “Failure to send me a comprehensive pension reform bill hurts our economy and costs Illinois taxpayers $17 million a day.”

Earlier this year, the Senate passed a rival pension plan that offers certain employees a choice between state subsidized health care or cost of living increases. Senate President John Cullerton has said that choice is critical to finding savings in the pension system while still obeying the state constitution.

With lawmakers scheduled to adjourn Friday, it’s not clear what a compromise between the House and the Senate will look like.

Meantime, the House of Representatives adopted a bill shifting the cost of pensions from the state onto universities and community colleges.

Universities had said the added costs will force them to raise tuition in the future, but those representing Illinois colleges still supported the measure.

“Why on earth they would agree to this is beyond me,” said Republican State Rep. Tom Cross.

In a committee Thursday, a spokesman representing universities said Illinois’ public universities wanted to be a part of helping the state with its public pension funding problem.

Tony Arnold covers Illinois politics for WBEZ. Follow him @tonyjarnold.