Elections in Nevada give the voter the choice to vote for "None of These" candidates listed. Every poll I see of the Illinois Senate race suggests to me that if Illinois put that option on the ballot, None of These would win.
The next bit of evidence for the pile: PPP's latest poll of the race.
Unlike many states we've seen, support for the PPACA runs relatively high: with 45% actually supporting it versus 43% who oppose it, meaning this had the marks of a close race before it began.
But since it did, both the Republican Mark Kirk and the Democrat Alexi Giannoulias have been hit by scandals, and support for both is running low. Giannoulias leads Kirk 31-30 (MoE 4.2), which is in line with previous polls I've seen.
PPP does throw in the wrinkle of a spoiler candidate, the Green Party's LeAlan Jones, who pulls in 14% support, and 26% of self-identified African American voters.
The poll asks about the Kirk scandal, with 10% saying Kirk was truthful about his military record, while 45% think he was lying. However no questions are asked about the Banking controversies surrounding Giannoulias, leaving us with only half the picture of why 39% of the electorate isn't ready to line up behind the Democrat or the Republican.