SPRINGFIELD – Illinois Senate President John Cullerton is defending attempts to fix the state's pension problem after an influential business group said it couldn't be done.

The Chicago Democrat released an open letter Thursday spelling out how proposed legislation to fill a huge funding gap in state-employee retirement systems would work and blaming Republicans for blocking it.

The letter was addressed to Tyrone Fahner, president of the Civic Committee of the Commercial Club of Chicago. Fahner released a memo Wednesday calling the pension crisis so big it's "unfixable."