Ameya Pawar

Illinois governor's race could be costliest in US history

The 2018 Illinois governor's race is on pace to be the most expensive in U.S. history, propelled by a wealthy Republican incumbent and a billionaire Democrat who are airing TV ads and hopping private planes to campaign events more than a year before Election Day.

J.B. Pritzker, an heir to the Hyatt hotel fortune and one of the world's richest people, is among several Democrats trying to defeat multimillionaire businessman-turned-governor Bruce Rauner. Also running is Democrat Chris Kennedy, nephew of the late President John F. Kennedy, who in a typical race might easily be the candidate with the biggest bank account.

But this is not a typical race. All of the candidates...