Illinois state Republican leaders say reforming the pension system must be a top priority in 2012. They’re calling on Democrats to help fix the state’s ailing system in the coming year.

Illinois is facing an $85 billion shortfall in eventual pension costs due to years of underfunding and the prolonged economic downturn.

Republican House Leader Tom Cross co-sponsored a pension reform bill with Democratic House Speaker Mike Madigan last year, but Madigan has yet to call it for a vote.

Cross said the bipartisan support needed to approve the bill is not there yet.

“It’s a very, very complicated issue and it’s going to take both parties working together and be willing to make some very very tough choices,” Cross told reporters Thursday.

That lack of action on pension reform was cited when Moody’s downgraded Illinois’ credit rating last week, making it the worst in the nation.

Gov. Pat Quinn, a Democrat, has pledged that reforming the state’s pension system would be one of his top priorities for the year.