First lady Laura Bush is scheduled to appear Thursday in suburban Chicago on behalf of McSweeney. Less than 24 hours before polls open, Illinois' two popular senators, Barack Obama and Dick Durbin, are expected to make an appearance for Bean.

Arizona Sen. John McCain spoke at a McSweeney fundraiser Monday, the second appearance by the likely 2008 presidential candidate. McSweeney's campaign to take Illinois's 8th district, one of the few Republican pickup opportunities, has been a veritable Who's Who of the GOP. President Bush, Vice President Dick Cheney, House Speaker Dennis Hastert, former New York City Mayor Rudy Giuliani, and House Majority Leader John Boehner have all promoted the former investment banker, who has dropped millions of his own fortune into the race. Former Chicago Bears coach Mike Ditka even dropped in for an appearance last year.

Bean's campaign has featured fewer heavy hitters, though former President Bill Clinton stumped for her last week. The one-term congresswoman, who upset long-serving GOP Rep. Phil Crane in 2004, has remained steadily ahead of McSweeney in polling, though her lead has careened from as low as 3 percentage points to as high as 19 in recent polls.

–Will Sullivan