By SARA BURNETT
CHICAGO (AP) -- State Sen. Daniel Biss said Monday he's running for Illinois governor in 2018, joining a growing field of Democrats hoping to unseat Republican Gov. Bruce Rauner.
The former University of Chicago math professor from Evanston said during an announcement streamed live via Facebook that it's time to take the state back from special interests that have controlled both parties.
"People across our state are hurting because of the nightmare of the last two years caused by Bruce Rauner," Biss said while seated in a Chicago office. "In Illinois billionaires and machine politicians have a monopoly on political power."
Several other Democrats already are vying to take on Rauner. Those who've already announced bids are businessman Chris Kennedy, the nephew of former President John F. Kennedy, Chicago Alderman Ameya Pawar, regional schools Superintengdent Bob Daiber and small business owner Alex Paterakis.
Billionaire businessman J.B. Pritzker said last week he's formed a campaign committee to explore a bid and was contributing $200,000 to fund its day-to-day operations.
Biss said he chose the format so he could speak one-on-one with voters and answer their questions, calling it the start of a "movement of the people." He used the discussion to call for an end to Illinois' nearly two-year state budget stalemate, better investment in schools and communities and a graduated income tax in which the highest earners pay a larger percentage of their income.
Biss, who graduated from Harvard University and earned a PhD from the Massachusetts Institute of Technology, served one term in the Illinois House before he was elected to the Senate in 2012. He considered a bid for comptroller last year but later bowed out.
He was among the harshest critics of Rauner and other Republicans during the 2016 campaign, creating a federal super PAC that spent millions on TV ads linking the governor to then-presidential candidate Donald Trump. The ads featured actors resembling Trump and Rauner in various scenes, including one in which they dined together then stuck regular people with their bill.
The Illinois Republican Party criticized Biss' connection to Democratic House Speaker Michael Madigan, calling him "the North Shore branch of the Madigan machine."
Spokesman Steven Yaffe noted Biss supported Madigan -- Rauner's chief adversary in Springfield -- for House Speaker and has taken campaign money from a political fund that Madigan controls. He called the super PAC that Biss formed a "Madigan political front group."
"Daniel Biss is a willing Mike Madigan accomplice who would give the Governor's office back to the Chicago machine," Yaffe said.
The GOP's strategy, which it has used with other potential and announced rivals, comes as a recent poll found Rauner's disapproval rating has almost doubled since just after he took office. Statewide, 58 percent of respondents disapprove of Rauner, according to the poll by the Paul Simon Public Policy Institute at Southern Illinois University.
But the poll also found the majority of residents disapprove of Madigan, the longtime speaker who also leads the Democratic Party of Illinois. According to the poll, 61 percent somewhat or strongly disapprove of Madigan. That's down from 63 percent last year.
Rauner, a wealthy former private equity investor, put $50 million into his re-election campaign fund last year -- money Republicans said was intended as a warning to possible opponents.
This story has been corrected to show that Biss was elected to the Illinois Senate in 2012, not 2014.