CHICAGO (CBS) — The owners of the Rivers Casino in Des Plaines have lost a three-year court battle with Cook County, over a slot machine tax approved by the Cook County Board.

Midwest Gaming & Entertainment had argued the state’s Riverboat Gambling Act prohibited such a tax at the county level, and that the tax also violated the Illinois Constitution, because it taxes slot machines at a higher rate than video gambling machines.

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The county’s tax on slot machines at casinos is $1,000 per machine, while the tax on video gambling machines used at bars and restaurants is $200 per machine.

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A Cook County Circuit Court judge struck down the tax last year, but an Illinois Appellate Court panel reversed that ruling a year later, and Midwest Gaming took the case to the Illinois Supreme Court, which has declined to hear the appeal, meaning the tax will stay in place.

“We are pleased with the Supreme Court’s decision confirming our long-held belief that the County’s tax on video gaming machines is legitimate and lawful,” Cook County Board President Toni Preckwinkle said in a written statement Wednesday morning. “The revenue generated from the gambling tax will help provide important funding for critical public safety services to County residents.”

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The county has not been collecting the tax since it went into effect in 2013, due to the litigation, but officials said they expect to collect $3 million in unpaid taxes now that the case has been resolved, and about $1 million per year going forward.