Illinois Republicans say they can still win the U.S. Senate race in four months even though their candidate resigned amid lurid sex allegations. Political analysts say that would take a miracle.

Republicans began searching for possible replacements soon after Jack Ryan (searchstepped down Friday. He is accused of trying to pressure his former wife, television actress Jeri Lynn Ryan (search), to have sex in public at clubs.

Party leaders insist all they need is the right candidate and the right amount of cash.

"There needs to be enough money to get the message out," said state Sen. Dave Syverson, treasurer of the Illinois GOP.

But Kent Redfield, a political science professor at the University of Illinois in Springfield, said the GOP's efforts to win the seat being vacated by retiring Republican Sen. Peter Fitzgerald was "an almost impossible task."

Democratic state Sen. Barack Obama held a wide lead over Ryan before the scandal broke, and many popular Republicans have kept their names off the list of potential candidates.

Kick-starting the campaign of a lesser-known Republican would cost several million dollars, Redfield said. He added that donors are likely to flinch at the prospect of contributing to what many regard as a doomed campaign.

"If it looks unwinnable, it is very difficult to raise money," he said. "You can't win because you can't raise money, and you can't raise money because you can't win."

Ryan's problems started in February, when his opponents in the primary called on him to release sealed records from a custody dispute with his ex-wife, who has had starring roles in "Star Trek: Voyager" and "Boston Public."

Ryan refused, saying the records would harm his young son if released, and repeatedly assured GOP officials and the public that the files contained nothing embarrassing.

But after Ryan won the Republican nomination, a judge agreed to open the records, revealing Jeri Ryan's accusations — which Ryan denies.

Four days after the files were opened, Ryan withdrew from the race.

The new Republican candidate should meet certain requirements to win, said Charles Wheeler, head of the Public Affairs Reporting program at the University of Illinois.

"It has to be a candidate who has no skeletons in the closet, who is articulate and who can raise money," he said. "It would help if they found someone who is a gazillionaire."

Republicans said they would begin interviewing possible candidates in the coming days and hope to name one by mid-July.

Redfield said the best Republicans can hope for is to prevent a bad situation from getting worse — and to ensure the U.S. Senate candidate doesn't hurt other Republicans in tight races for state offices.

"They wanted to put a new face on the Republican Party and that was supposed to be Jack Ryan," said Redfield. "Now, they just want to look credible and stop the bleeding."

Those who have declined to run include former Gov. Jim Edgar, Illinois Republican Party chairwoman and state treasurer Judy Baar Topinka, and former Gov. James Thompson.

One leading possible replacement is state Sen. Steve Rauschenberger, who finished third in the Republican primary. Also on the list are dairy owner Jim Oberweis, businessman Andy McKenna and former chairman of the State Board of Education Ron Gidwitz.