(CNN) - CNN Thursday turned the important battleground state of Wisconsin from "lean Obama" to true "toss up" on its electoral map, in the wake of Mitt Romney's naming of House Budget Chairman Paul Ryan, a seven term congressman from the Badger state, as his running mate.
One contributing factor behind CNN's move was a new poll that matched two others from last week that indicate that the presidential contest in Wisconsin is close. While Ryan's announcement did not dramatically alter the presidential poll numbers in Wisconsin, it did change the way both campaigns viewed the state of the race in the state.
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"Both campaigns see the Ryan pick as something that makes Wisconsin more competitive. When we visited this week, every Republican we spoke to suggested it would help keep a Republican base already energized by the recent recall election fired up and hungry for more in November." said CNN Chief National Correspondent John King.
"And we saw the impact on the Obama campaign firsthand. Within hours they rewrote their script for calls to voters to add some sharp criticism of Ryan and his Medicare plan. But the way they did it was telling: A couple of lines about how is a nice guy, sure, but then the segue to the attack and a script that included a line saying President Obama was more in tune with working class voters," added King.
According to the CNN/ORC International survey, which was conducted entirely after Romney added Ryan to the GOP ticket, 49% of registered voters in Wisconsin say they back President Barack Obama, with 45% supporting Romney. The president's four point advantage over the presumptive Republican presidential nominee is within the survey's sampling error.
Two other polls conducted last week, before the Ryan announcement, indicated the president holding a single digit advantage in a state he won by 14 points in the 2008 presidential election.
Wisconsin now becomes the eighth state CNN considers a true toss up, joining Colorado, Florida, Iowa, Nevada, New Hampshire, Ohio and Virginia. CNN considers Michigan, New Mexico, and Pennsylvania as states that lean towards Obama, with Arizona, Indiana, Missouri and North Carolina as states that lean towards Romney.
With Wisconsin's move to true "toss up," the CNN Electoral Map now suggests Obama leading in states with a combined 237 electoral votes, Romney ahead in states with a combined 206 electoral votes, and states with 95 electoral votes up for grabs. 270 electoral votes are needed with win the White House.
While Obama won Wisconsin by double digits, Sen. John Kerry, the 2004 Democratic nominee, narrowly captured the Badger State, over President George W. Bush, and Vice President Al Gore edged out Bush in the state in the 2000 contest. It appears the 2012 contest in Wisconsin will be much closer to those competitive contests than the 2008 election.
"The longer term history is on the president's side, but the last couple of years have been good for Republicans. If nothing else, the president is going to have to fight harder – and that means time and resources in Wisconsin that otherwise might have gone to a North Carolina or Colorado. Anything Romney can do to expand the map helps, and this at least for now expands the map," adds King.
While the CNN poll suggests the Ryan announcement barely moved the needle in his home state, the news shouldn't come as surprise.
"That's in keeping with political wisdom which says that Americans pay little attention to the bottom of the ticket , even in the running mate's home state, if he has never run for statewide office," says CNN Polling Director Keating Holland.
But the survey does indicate Ryan's popular in his home state. His favorable rating, at 50%, is actually higher than Romney's, and 56% of all Wisconsinites say that Ryan is qualified to serve as president if necessary, and most rate Romney's pick of Ryan as excellent or pretty good.
According to the poll, the Romney/Ryan ticket is doing best in the southeastern part of the Wisconsin, Ryan's home base. They also do best in outer suburbs that are far removed from major population centers like Milwaukee or Madison - a good description of much of Ryan's congressional district. Obama continues to pile up votes in Milwaukee and Madison, but he is also winning the "Big Woods" area of Wisconsin in the northwestern part of the state - an area he carried four years ago.
"Ryan gets his highest favorable rating among Wisconsinites who consider themselves members of the Tea Party. Tea Partiers are wild about Ryan - 87% have a favorable view of him. His favorable rating is higher among men than women, among higher-income Wisconsin residents than lower-income, and among those outer suburbs that are similar to the places Ryan represents in Congress," adds Holland.
But the survey indicates Wisconsinites are less familiar with Ryan the further they live from the First Congressional District. Only one in ten who live near his district are unsure how they feel about Ryan, but that rises to one in four in the northwestern part of the state.
The CNN poll was conducted by ORC on Monday and Tuesday, with 1,005 Wisconsin adults, including 920 registered voters, questioned by telephone. The survey's overall sampling error is plus or minus three percentage points.
CNN Political Editor Paul Steinhauser contributed to this report.