CHICAGO (CBS) — Lawmakers could be staring at another special session, because of a dispute over education funding, after Gov. Bruce Rauner gave Democrats an ultimatum on Friday.

The Illinois General Assembly has passed legislation to change the way the state doles out money for public schools, but Senate Democrats have held onto the bill rather than sending it to Rauner, who is threatening to use his amendatory veto power to remove about $300 million in pension funding for the Chicago Public Schools.

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“I want that bill. That bill must be on my desk by noon on Monday. Noon on Monday, send education funding to my desk. Noon on Monday, and if it is not on my desk by noon, I will call special session of the General Assembly, demand that they come back here to Springfield, and do their jobs. Every day until we get schools funded and open on time,” Rauner said.

The school finding plan, known as Senate Bill 1, is a historic measure. It re-writes Illinois’ current school funding formula, which is recognized as both inadequate and inequitable.

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No school district would receive less funding, but poor districts would receive substantially more.

Rauner says he is opposed to SB 1 because it favors Chicago at the expense of other districts. He says the plan includes a pension bailout for CPS, and believes that money should go to school districts across the entire state.

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The governor said he wants the education funding plan resolved by the end of the month.