And Rauschenberger says he's running alongside gubernatorial candidate Ron Gidwitz.
The Elgin Republican and the Chicago businessman appeared together at a news conference this morning.
The move combines Gidwitz's personal fortune with Rauschenberger's appeal to conservatives. Together they present a potentially powerful challenge to the front-runner for the GOP nomination, state Treasurer Judy Baar Topinka.
Rauschenberger has been the chief budget expert for Senate Republicans. Gidwitz is the heir to the Helene Curtis cosmetics fortune and former chairman of the State Board of Education.