Claire McCaskill is leading by a point in the Missouri Senate race, where polling hasn't really produced a clear picture, and Obama is up by a wide margin in his home state of Illinois. Here's our guide to today's polls and why they matter.

Findings:  Claire McCaskill leads in a very tight Missouri Senate race with 45 percent to Todd Akin's 44 percent. 
Pollster: Public Policy Polling
Methodology: Automated poll of 621 likely voters in Missouri August 28 and 29 with a margin of error of +/-3.9 percent.
Why it matters: It's been confusing to pin down what exactly is happening in the Missouri Senate race after Todd Akin's "legitimate rape" comments based on poll results. In yesterday's Poll Watch we saw a poll from the conservative Family Research Council that had Akin leading McCaskill by three points and another recent poll gave McCaskill a nine-point lead. Today's poll reverses the course for PPP, which found in a poll last week Akin leading by a point. This finding led National Review's Jim Geraghty to criticize the left-leaning pollster for skewing the sample toward Republicans so that Akin wouldn't drop out.
Caveat: PPP does lean left. Also, don't think this poll doesn't show some good news for Republicans in the state: Romney maintains a 12-point lead over Obama. 


Findings: Obama leads in Illinois by a whopping 55 percent to 29 percent.
Pollster: Crain's/Ipsos 
Methodology: Internet survey of 600 voting-age residents August 17 through 23 with a margin of error of +/-4.7 percent.
Why it matters: This is not really surprising given that this is the president's home-state. Crain's Greg Hinz explains that there's some even worse news for Republicans. "Romney needs to show at least some pockets of strength to help other Republicans, especially in four hotly contested congressional races in the north and west Chicago suburbs." He continues: "The poll makes clear that this task — running strongly enough to help other Republicans — is getting harder."
Caveat: Another poll this month, reported in the conservative Daily Caller, showed Obama leading Romney in 49 percent to 37 percent in Cook County. The Daily Caller's Alexis Levinson wrote: "That puts him ahead by a far thinner margin than expected in a county he should be winning handsomely."