Still deciding whether to run, former Wisconsin Gov. Tommy Thompson (R) holds a slim lead over Sen. Russ Feingold (D) in a hypothetical Senate matchup, according to Rasmussen (March 16, 500 LV, MoE +/- 4.5%). Thompson led by 5 points a month ago, but now leads by just 2 points -- a statistical tie.

Feingold increased his leads over two other potential GOP opponents, Dave Westlake and Terrence Wall.

Thompson 47 (-1 vs. last poll, Feb. 17)
Feingold 45 (+2)
Und 4

Feingold 51 (+4)
Westlake 35 (-2)
Und 10

Feingold 49 (+2)
Wall 40 (+1)
Und 7

Click here to see previous polling for this race.

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