Since March’s primary election, Democratic gubernatorial nominee J.B. Pritzker has spent more than $21 million, more than doubling the $8.4 million spent by Republican incumbent Bruce Rauner.

That’s a marked reversal from 2014, when Rauner outspent his Democratic opponent three-to-one over the same period.

This year, Democrats have their own rich guy.

Together, Rauner and Pritzker spent nearly $300,000 a day from March 21 to the end of June, still on pace for the most expensive governor’s race in American history.

Quarterly reports filed Monday are the first detailed records of Pritzker and Rauner’s finances since they won their party’s primaries.

That breaks down to $207,444.52 a day for Pritzker, and $83,023.42 for Rauner.

Rauner’s spending is up by more than $2 million from his spending in the same period during the 2014 election. A more dramatic transformation is underway on the Democratic side of the race.

Four years ago, then-Gov. Pat Quinn spent only $1.74 million during the comparable period. This year, Pritzker has dished out more than that on individual advertising buys.

Overall, Rauner has reached into his own pockets to give $57.5 million to his campaign since the beginning of 2016, compared to $100 million from Pritzker. To make up the difference, Rauner has relied on donations from business-people and especially financiers, such as hedge fund manager Ken Griffin, who has given more than $20 million since early 2016.

Of Pritzker’s post-primary spending, more than $3.2 million went to other Democrats, including $1 million each for House Speaker Mike Madigan’s Democratic Majority fund and the Rock Island County Democratic Central Committee. The billionaire gave $500,000 to both Senate President John Cullerton’s Senate Democratic Victory Fund and the Illinois Democratic Heartland Committee, a Downstate fund.

Rauner spent a fraction of that number — a little over $100,000 — supporting fellow Republicans.

The budgets for both candidates were dominated by multi-million dollar advertising buys.

This already explosive pace of spending is presumably only the beginning: Rauner had more than $31 million left to spend at the end of June, compared to more than $18 million for Pritzker. But both candidates have the personal wealth presumably to add to their kitties whenever they wish.

It’s all adding to expectations that the Pritzker-Rauner race will break the record $280 million spent in California’s 2010 gubernatorial race.

The spending comes on the heels of an already expensive primary campaign. The Sun-Times calculated that each candidate spent around $120 for every vote counted for them on March 20.

In other races, Republican nominee for Attorney General Erika Harold has spent a little over $100,000 in April, May and June — about half as much as her Democratic opponent state Sen. Kwame Raoul.  She ended June with about $230,000 in the bank on June 30, compared to $780,000 for Raoul.

Further down-ballot, campaign reports for the three-month period show strength for Democratic incumbents in statewide races. Democratic incumbent Comptroller Susana Mendoza spent three times as much as Republican challenger Darlene Senger, and ended the reporting period with 43 times as much cash on hand. Democratic Treasurer Michael Frerichs had $1.2 million on hand, compared to a $32,000 for Republican Jim Dodge.

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