SPRINGFIELD, Ill. (AP) — Billionaire Ken Griffin made his support for a Republican governor official on Monday, contributing $20 million to Aurora Mayor Richard Irvin in his quest to replace Democratic Gov. J.B. Pritzker.

Griffin had previously expressed admiration for Irvin’s background as a military veteran, litigator and Aurora’s first Black mayor. As for supporting a particular candidate, Griffin had said on that he was “all in” to upend Pritzker, pledging up to $300 million to defeat the first-term Democrat.

Other Republicans running for governor include state Sen. Darren Bailey of Xenia, former Sen. Paul Schimpf of Waterloo, equity investor Jesse Sullivan of Petersburg and Bull Valley business owner Gary Rabine.

Griffin’s money all but single-handedly defeated Pritzker’s 2020 ballot measure to allow a graduated income tax that would have taken a greater share from the wealthy. The CEO of multinational hedge fund Citadel, Griffin also contributed heavily to former Republican Gov. Bruce Rauner’s 2018 failed reelection bid against Pritzker.

“Richard knows the importance of ending wasteful spending and reducing oppressively high taxes,” Griffin said in a statement. “Illinois taxpayers are tired of sending their hard-earned money to Springfield to be burned in the furnace of waste and corruption.”

Pritzker, who financed his own campaign in 2018, defeated Rauner in what became the second-most expensive gubernatorial race in history at more than $200 million. Rauner was unpopular after a two-year budget stalemate with Democrats who controlled the Legislature.

“Ken Griffin would conveniently like us all to forget he bankrolled the very governor that decimated the social services that prevent violence, caused our colleges and universities to nearly lose accreditation, and devastated our state’s finances in previously unseen ways,” Pritzker campaign spokeswoman Natalie Edelstein said.

Pritzker faces a Democratic primary challenge from Chicago activist Beverly Miles.