Former Sen. Russ Feingold, a hero to Wisconsin liberals, told supporters Friday that he will not run for polit...

Former Sen. Russ Feingold, a hero to Wisconsin liberals, told supporters Friday that he will not run for political office in 2012, the Milwaukee Journal Sentinel reported.

Feingold would have been the Democratic front-runner for the Senate seat or for governor in a possible recall election of Gov. Scott Walker.

He did not rule out a return to politics but said it will not happen next year.

“While I may seek elective office again someday, I have decided not to run for public office during 2012,” he said in the early-morning email to supporters, according to the paper.

Feingold’s decision leaves Rep. Tammy Baldwin (D-Wis.) as the Democratic front-runner for the Senate seat being vacated by Sen. Herb Kohl (D-Wis.). Former Gov. Tommy Thompson and former Rep. Mark Neumann are considered likely to enter the race on the GOP side.

A Public Policy Polling survey released Thursday found that Feingold is “still the best-known and and best-liked of the candidates,” with a statewide favorable rating higher than Thompson, Baldwin, Neumann and Democratic Rep. Ron Kind and former Rep. Steve Kagen.

The poll found Feingold narrowly leading head-to-head matchups with both Thompson and Neumann, who lost a 1998 race against Feingold and the 2010 gubernatorial primary to Walker.