The latest poll from the Marquette University Law School has Tommy Thompson leading the pack for the GOP's U.S. Senate nomination.
The survey found 28 percent of respondents backed Thompson, compared to 20 percent for Eric Hovde, 18 percent for Mark Neumann and 13 percent for Jeff Fitzgerald. Twenty-one percent of respondents were undecided.
When leaners were added in, it was Thompson 33, Hovde 24, Neumann 21 and Fitzgerald 15 with 7 percent undecided.
The GOP primary results were based on 519 live interviews of likely voters both through landlines and cell phones. The margin of error for the primary survey was plus or minus 4.4 percentage points.
In last month's Marquette poll, it was Thompson 35, Hovde 23, Neumann 10 and Fitzgerald 6.
Looking to November, the Marquette poll found Thompson was the only GOP candidate to top Dem U.S. Rep. Tammy Baldwin. Forty-eight percent backed the former guv when paired against Baldwin, who was supported by 43 percent of respondents. She was tied with Neumann at 44 percent apiece, and edged Hovde 44-41 and Fitzgerald 45-40.
All four match ups were within the poll's margin of error and were little changed from last month's survey.
In the presidential race, President Obama led Mitt Romney 50-45, compared to a 51-43 spread in last month's survey.
The sample for the November match ups included 1,188 likely voters and had a margin of error of plus or minus 2.9 percentage points.