Paul Ryan helps Mitt Romney take a one-point lead in Wisconsin, but another poll shows that more Americans don't like his Medicare proposal than do. Separately, a poll shows Todd Akin maintaining a one-point lead in the Missouri Senate race. Here's our guide to today's polls and why they matter.

Findings: Mitt Romney takes a tiny lead in a PPP poll of Wisconsin, where Obama held a seven-point lead in their last poll. Romney now leads by a point — 48 percent to 47 percent — in what Politico's Alexander Burns calls a "statistical tie."
Pollster: Public Policy Polling
Methodology: Automated poll of 1,308 likely Wisconsin voters August 16 through 19 with a margin of error +/-2.7 percent. 
Why it matters: Ryan serves as congressman in Wisconsin and his addition to the ticket helps Romney in this state. That said, it's still a one-point race. According to PPP: "A big reason Wisconsin remains so competitive for the GOP is that the electorate looks like it will be considerably more Republican leaning than it was in 2008, reflecting the continued high energy level of the party's voters after its victory in June's recall election." Politico's Burns writes: "The race has now caught up with that assessment and there's a real chance of a dogfight in a state that hasn't voted for a GOP presidential candidate since 1988." 
Caveat: PPP leans left. 

Findings: More registered voters — 45 percent — oppose Paul Ryan's proposed Medicare reforms, than those that support them at 36 percent.  
Pollster: Public Policy Polling for Daily Kos/SEIU
Methodology: Poll of 1,000 registered voters August 16 through 19 with a margin of error of +/-3.1 percent.
Why it matters: Tom Kludt at Talking Points Memo points out that the poll "lends credence to what Democrats — and even some Republicans — have warned about Paul Ryan being thrust onto the GOP ticket: Most Americans don’t much care for the Wisconsin Congressman’s sweeping proposal to reform Medicare." Daily Kos itself writes: "It's clear what the Obama campaign and congressional Democrats need to do: relentlessly hammer the message that the Ryan/Romney plan is vouchers."
Caveat: We noted PPP's bias before and Daily Kos is liberal. 

Findings: Despite his comments about rape, Todd Akin still leads Claire McCaskill in the Missouri Senate race by one point in a new poll: 44 percent to 43 percent. 
Pollster: Public Policy Polling
Methodology: Automated poll with 500 likely Missouri voters August 20 with a margin of error of +/-4.4 percent.
Why it matters: Though even Republicans have called for Akin to leave the race, this poll implies that his comments haven't much changed voters opinions since PPP's poll in May where he led by the same margin. 
Caveat: Though, as we mentioned, PPP normally skews left, Jim Geraghty at National Review Online points out that for this poll there is a larger sample of Republicans. He writes: "Anyone suspect that the Democrat polling firm might be trying to get the result they want, to ensure Akin stays in, so that he can get pummeled in November?"

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Esther Zuckerman