Former Speaker Dennis Hastert (R) is expected to endorse dairy scion Jim Oberweis (R) today, ending months of speculation and capping a bizarre week in which one Republican primary candidate begged the former high school wrestling coach to stay publicly neutral in the hard-fought contest to replace him.

Neither Oberweis’ campaign nor Hastert associates would confirm the endorsement, but Oberweis has scheduled a news conference today with “a special guest … to announce a major endorsement.”

State Sen. Chris Lauzen, who according to recent polls is clustered atop the Republican primary heap with Oberweis, asked Hastert in a local newspaper Monday to remain on the sidelines.

“Most people to whom I listen are pretty sick these days of the results that have been produced by big money and big clout in Washington, D.C. and Springfield,” Lauzen wrote. You can provide leadership by letting the people decide and using your very substantial experience and skills to coach your successor. In this way, you are a winner no matter whom the people choose.”

The political rivalry between Lauzen, considered by some to be a party maverick, and Hastert, a longtime powerbroker in the state GOP, is widely known in Windy City political circles, although Hastert’s choice of Oberweis was hardly a given. Oberweis, whose significant personal fortune would relieve pressure on the cash-strapped National Republican Congressional Committee, was in Washington, D.C., Wednesday meeting with party officials.

Geneva Mayor Kevin Burns is also seeking the Republican nomination.

Meanwhile, the Illinois chapter of the Service Employees International Union has endorsed ex-Fermilab physicist Bill Foster, his campaign announced Wednesday. Foster is the leading Democrat in the race to replace Hastert.

SEIU represents more than 165,000 health care workers, security guards, bus drivers, paralegals and janitors in the state.

— Matthew Murray and Nathan L. Gonzales