Illinois politicians this week must reveal who gave them donations over the past three months, and how much they gave. The results could be a strong indicator of which candidates are ready for the 2012 elections, and which candidates are vulnerable.

In 2012, Illinois voters will fill 18 seats in the U.S. House, and all 177 seats in the state legislature. Candidates for those offices will be running in districts with brand new boundaries, because of the redistricting process that takes place every ten years. These races can be more expensive than normal, even for longtime incumbents. That’s in part because they have to introduce themselves to voters in areas they didn’t used to represent.

It’s still relatively early in the election cycle, so many candidates will report next to no donations. But politicians expecting tight races want to show big numbers, hoping to scare off potential challengers. And challengers want to show they can raise cash, so they’ll be taken seriously by the media and interest groups. The deadline for campaigns to report donor information from the past three months is this Friday night at midnight.