A new poll shows Sen. Russ Feingold (D-Wis.) trailing former Gov. Tommy Thompson (R) by 12 points, 51-39.

As Thompson wieghs whether to enter the race against Feingold, the polling has largely been encouraging. The latest poll, from the conservative Wisconsin Policy Research Institute, is his biggest lead yet.

Rasmussen had Thompson ahead 47-43.

Whether the polls are accurate or not, it seems pretty apparent Thompson would make this race something along the lines of a toss-up. He appears to be getting closer to running, and a significant challenge to Feingold would be a big coup for the NRSC.