(CNN) - A new poll suggests that Sen. Russ Feingold of Wisconsin is fighting for his political life.
A CNN/Time/Opinion Research Corporation poll released Wednesday indicates that the three-term Democratic senator trails businessman Ron Johnson, the Republican nominee Senate nominee, 52 to 44 percent among likely voters in Wisconsin. Johnson's eight point lead is up from a five point advantage in mid September.
Full results (pdf)
Among the larger sampling of registered voters, Johnson, who enjoys the support of many in the Tea Party movement, has a 48 to 45 percent advantage, up from a two point margin last month.
According to the poll, Feingold has an overwhelming advantage among Democrats, while Johnson has an overwhelming advantage among Republicans and leads 57 to 38 percent among independent voters.
"Although Johnson is from Oshkosh, he manages no better than a tie in the northeastern part of the state, but he has a two-to-one lead in the Milwaukee suburbs and other parts of the southeastern region, and that's enough to give him a statewide lead," says CNN Polling Director Keating Holland. "Feingold is picking up votes in the two major Democratic strongholds in the state - Milwaukee and the southwestern region that is dominated by Madison, the state capital."
"The two Senate candidates are tied among women, with 48 percent apiece," Holland also notes. "That's usually bad news for Democratic candidates and it hurts Feingold as well, given Johnson's 15-point lead among men."
The Senate showdown isn't the only political battle attracting attention in the Badger State. There's also a closely watched governor's race between Milwaukee Mayor Tom Barrett, a Democrat, and Milwaukee County Executive Scott Walker, a Republican.
The survey indicates that Walker has a 52 to 44 percent lead over Barrett among likely voters, down from an 11 point lead in mid September. Among registered voters, Walker has a 48 to 45 percent advantage, unchanged from last month.
According to the poll, Walker leads by 22 points among independent voters. The winner in November succeeds Democratic Gov. Jim Doyle, who decided against running for a third term this year.
According to the survey, 44 percent of likely voters approve of the job President Barack Obama's doing in the White House, with 52 percent saying they disapprove. Among all adults, 45 percent give Obama a thumbs up while 49 percent disapprove.
The CNN/Time/Opinion Research Corporation poll was conducted October 8-12, with 1,506 adults, including 1,372 registered voters and 931 likely voters questioned by telephone. The survey's overall sampling error is plus or minus 2.5 percentage points, with a sampling error of plus or minus 3.5 percentage points for likely voters.
- CNN Deputy Political Director Paul Steinhauser contributed to this report
Get the latest poll results here.