A more likely candidate could be state Attorney General J.B. Van Hollen, who first won statewide in 2006, a tough year for Democrats. He was re-elected last year with 58 percent of the vote and would not need to give up his post to run for the seat.
Other potential Republican candidates include two previous Senate candidates — former Rep. Mark Neumann, who ran for governor last year and lost to Feingold by 3 points in 1998, and wealthy businessman Tim Michels, who lost to Feingold by 11 points in 2004.
Democrats note that President Barack Obama competed hard there in 2008 and won the state by 14 points.
“This is a blue seat that will stay blue in a blue year in Wisconsin,” a Wisconsin-based Democratic strategist said. “It’s a presidential year. Scott Walker may be on the ballot — he’s totally activated the Democratic base.”
The National Republican Senatorial Committee had this to say:
“Senator Kohl’s retirement, just like his Democrat colleagues who stepped aside before him, immediately presents another key opportunity for Senate Republicans next year. It also further dilutes the ability of national Democrats to go on offense, while they fight to maintain their dwindling Senate majority.”
One well-placed Republican operative also suggested Republican National Committee Chairman Reince Priebus as a possible candidate.
The Republican operative, who knows Priebus and has worked extensively in Wisconsin, said he anticipates an effort in the Badger State to get Priebus to come home and bid for the Senate, but the source expressed skepticism that the RNC chairman would actually run for the seat.
Shira Toeplitz and Nathan Gonzales contributed to this report.
Former Sen. Scott Brown, R-Mass., candidate for U.S. Senate in New Hampshire, holds his hand over his heart during the singing of the national anthem as he waits to take the stage for his town hall campaign rally with Sen. John McCain at the Pinkerton Academy in Derry, N.H., on Monday, Aug. 18, 2014.