A new Rasmussen survey conducted June 5th of 500 likely voters in the Badger State finds Barack Obama leading John McCain 45 to 43 percent—within the poll’s margin of error. Six percent would support some other candidate and six percent were undecided.

The new poll continues a 3-month trend with neither candidate able to pull away from the other in Wisconsin—a classic battleground state in presidential elections. In 8 public polls conducted by 4 different polling organizations since mid-March, neither Obama nor McCain has mustered an advantage of larger than 6 points.

Overall, however, Obama seems to have maintained a slight advantage in Wisconsin: Obama has polled ahead of McCain in 10 of 14 public polls dating back to November 2007, and McCain has not held a lead of greater than 4 points in any poll. But Obama’s double-digit leads measured in two polls of registered voters by SurveyUSA in February 2008 have largely evaporated back to a dead heat matchup with McCain.

McCain’s competitive campaign in Wisconsin thus far is particularly impressive considering the negative views held by Badger State residents towards President George W. Bush. In the new Rasmussen survey, Bush’s disapproval rating is 68 percent, with only 31 percent approving of his job performance.