SPRINGFIELD — A leading Illinois Republican says the state should not sell the Thomson Correctional Center for less than a quarter of a billion dollars.

Senate Minority Leader Christine Radogno said that amount could cover the costs of construction and the mortgage payments that have been made since the prison was completed in 2001, as well as account for increases in labor and materials.

“I believe we ought to get a premium,” the Lemont Republican said.

It remained unclear Wednesday how much the state will get from the federal government for selling the mostly unused 1,600-cell maximum-security lockup.

In comments to reporters at the Statehouse Wednesday, Gov. Pat Quinn said that under state law the sale price will be determined by third-party appraisals that haven’t yet happened.

Quinn wouldn’t commit to a price he hopes to get.

“We want to make sure we get fair market value for it,” Quinn said.

Radogno said Illinois should force the federal government to pay top dollar for the nearly unused facility because it will help President Barack Obama keep a campaign promise to close the terrorist detention center in Guantanamo Bay, Cuba.

“We deserve a premium for bailing out the Obama administration,” the Lemont Republican said.

In addition, Radogno said, Obama is aware his home state is having massive budget problems.

“He knows we need the money,” Radogno said.

If the sale goes through, Radogno said, the money should not go toward the state’s current budget problems. Rather, she said, the money should be banked in order to pay for prison expansions in the future.

Quinn offered no timetable for what comes next in the Thomson sale. A panel of lawmakers is set to meet Tuesday in Sterling to hear debate over the proposed closure.