SPRINGFIELD, Ill. (NEXSTAR) — A third former state legislator has filed a lawsuit to argue he is entitled to pay raises from years past — even though he voted against them while he was in office.

Mike Fortner, a former Republican state representative and NIU physics professor from West Chicago, had a reputation for paying close attention to the state’s many fiscal headaches.

Fortner filed the new lawsuit on Tuesday seeking backpay for himself and all current or former state lawmakers. His lawyers argue Fortner’s previous votes to block his own pay raises were unconstitutional because it changed his salary during the middle of his term.

“Fortner is entitled to receive his full COLA salary adjustments for the period from July 2009 to January 2019 — spanning all of fiscal years 2010 through 2018 and the first six months of fiscal year 2019,” the suit argues.

Fortner’s attorneys later filed a motion for class action certification on Wednesday, which would extend to all current and former members of the General Assembly — even those who don’t publicly put their names on the lawsuit.

Comptroller Susana Mendoza (D-Illinois) called it “an ill-advised class(less) action lawsuit” that “exposes taxpayers to millions of dollars in additional liability.”

Mendoza’s office estimates the class action lawsuit could cost taxpayers more than $10 million if the courts rule in Fortner’s favor.

“I respectfully suggest that this Professor of Particle Physics has sued the wrong person – he should sue himself,” Mendoza said. “HE is the one who voted to deny himself a pay raise – not the Comptroller’s office. It’s not rocket science, Professor. You should know better.”

In the early 2010s, elected officials won glowing headlines for embracing fiscal discipline in forgoing their annual cost-of-living adjustment (COLA) pay raises. Governor Pat Quinn signed several laws to require legislators to take furlough days as another way to reduce their pay. Now, Fortner’s lawsuit argues both were unconstitutional, and asks the court to order the Comptroller to reimburse him.

Last year, statehouse Democrats took a new approach to block their automatic pay raises. Instead of writing conflicting language in the budget that could contradict the state constitution, they simply zeroed out the line item in the appropriations bill next to the legislator pay raises.

“They absolutely could have” done that again this year, Comptroller Susana Mendoza’s spokesman Abdon Pallasch said in a phone call Thursday night. Instead, this new state budget gives lawmakers their full COLA.

The Illinois House filed the final budget bill with 20 minutes to go before a midnight deadline on Monday. When the 3,088-page piece of legislation arrived in the Senate for final approval, downstate Senators Doris Turner (D-Springfield) and Rachelle Crowe (D-Glen Carbon) were so surprised to see the legislator pay raises were added back into the bill that they voted against it.

Two other former state senators, Michael Noland (D-Elgin) and James Clayborne (D-Belleville), have gone back and forth against the Comptroller’s office in court, claiming they were entitled to reimbursement for lost wages. Both Noland and Clayborne also voted against pay raises while they were in office, and sued for them in court after they left Springfield.

A judge recently awarded Noland and Clayborne a victory and ruled they do have a right to back pay. Mendoza has not issued them checks, and has appealed the decision, saying she will take the fight all the way to the state Supreme Court.

Court records list Eric Madiar as one of Fortner’s attorneys in the new lawsuit. Madiar served as former Senate President John Cullerton’s chief legal counsel before leaving state government to open a lobbying firm. As the Senate Parliamentarian, Madiar would have signed off on the maneuver when Noland, Clayborne, and Fortner voted to block their own pay raises.

If the courts ultimately decide the constitutional guarantee of a COLA supersedes the General Assembly’s power to appropriate funds for their own salaries, politicians could still find a way to publicly denounce the raise and donate the funds.

“I will send legislators the forms state employees can already use to distribute a portion of their salaries to charity,” Mendoza said. “As a former legislator who voted against these pay raises, I will lead by example, donating any back pay I get to charity and will encourage others to do the same.”