Baldwin has released two television ads attacking Thompson since he emerged from the hotly-contested GOP primary. In a spot released earlier Wednesday, Baldwin criticizes Thompson for refusing to release his tax returns. Thompson also faced a deluge of negative ads in the weeks leading up to the primary. Trying to cut into the former governor's early lead in the polls, businessman Eric Hovde and former Rep. Mark Neumann painted him as a moderate Republican and accused him of supporting Obama's signature health care law. Those ads took a toll on Thompson, but his favorability numbers are better than Baldwin's heading into the general. In the new poll, 40 percent of registered voters said they have a favorable view of Thompson, while 38 percent said they have an unfavorable view of him. Asked about the less-known Baldwin, 32 percent of registered voters said they have a favorable view of the congresswoman, while 37 percent said they have an unfavorable view. The survey of 706 registered voters has a margin of error of plus-or-minus 3.8 percentage points, while the subsample of 576 likely voters carries a margin of error of plus-or-minus 4.2 percentage points.