Illinois Attorney General Lisa Madigan on Friday issued formal opinions targeting Gov. Bruce Rauner’s proposals to weaken labor unions, calling both illegal under federal and state labor laws.

Madigan’s opinions target two Rauner proposals: one to create “right-to-work zones” where union membership would be voluntary and the other to allow governments to opt out of prevailing wage agreements on public works projects.

In his February budget address, Rauner said reforming the prevailing wage laws could save the state’s schools nearly $160 million every year. He said restructuring the bidding for construction projects would save taxpayers billions.

Last month, Rauner issued an executive order banning the collection of fair-share fees. And anticipating a legal challenge, he filed a lawsuit against two dozen unions and brought in an outside law firm to handle the case pro bono. Madigan has filed a motion challenging the executive order.

In the opinion on prevailing wage agreements, Madigan wrote that they are meant “to encourage the efficient and expeditious completion of public works by ensuring that workers receive a decent wage.”

She wrote that all counties, municipalities and school districts must comply with the provision when seeking bids and awarding contracts for public works projects.

“Neither home rule nor non-home-rule units have the authority to opt out of compliance with its requirements by the adoption of an ordinance or resolution or pursuant to referendum,” she wrote.

Regarding “right-to-work zones,” Madigan wrote that Rauner’s proposal would violate the federal National Labor Relations Act, which she said preempts the regulation of union security agreements in all instances that impact interstate commerce. She wrote the only exception is a section which permits only states to enact statewide right to work laws.

“States are authorized to prohibit union security agreements on a statewide basis. To date, 25 states have enacted constitutional provision or statutes limiting the use of union security agreements. Illinois does not have such provision in its laws,” Madigan wrote.

In a statement, Rauner spokesman Lance Trover said the administration remains “confident” regarding their “right to work zones.”

“The Rauner administration respectfully disagrees with the Attorney General’s opinion regarding local right-to-work,” Trover said. “The administration is confident that with enabling legislation from the state, local governments can create employee empowerment zones.”