No Republican has come forward yet to challenge Sen. Herb Kohl (D-Wis.) in 2006. Considering that a GOPer would need to begin raising money immediately to credibly take on the multimillionaire three-term Senator, it is likely that no big-name challenger is on the horizon.

Of course, outgoing Health and Human Services Secretary Tommy Thompson (R) has not closed the door on returning to elective politics in Wisconsin, but no Badger State political watcher believes the former governor is serious.

Asked about a political comeback earlier this month, Thompson told The Associated Press: “That’s entirely possible. I happen to love politics. Why would I say no? There’s a Senate seat open.”

The only problem is the seat is not actually open.

“Senator Kohl has already said he intends to run for re-election in 2006,” said Kohl’s communications director, Lynn Becker.

Even if the Senate race turns out to be a snoozer in 2006, there could still be several competitive races in the Dairy State. Powerful Republicans, including Rep. Mark Green, are considering challenging first-term Gov. Jim Doyle (D). And Republicans in the northeast part of the state are already mobilizing in case Green runs for governor.

Meanwhile, Thompson’s future continues to intrigue his former constituents.

Dave O’Neill, a Wisconsin-based GOP consultant and fundraiser, said he does not expect Thompson to challenge Kohl.

“The only name thrown around is Tommy’s but I don’t think it’s serious at all,” he said.

Another Republican operative, who did not want to be named, said Thompson was just being Thompson.

“Tommy likes to keep that speculation going … he’s a master at it,” the source said.

Seth Boffeli, spokesman for the Wisconsin Democratic Party, said Thompson is famous for floating his name for lots of positions.

“Tommy Thompson likes to keep people in Wisconsin guessing about what he’s going to do next,” Boffeli said.

While Republicans may salivate at the prospect of a top-tier candidate such as Thompson challenging Kohl, whose family owned the supermarket and retail chain of the same name until 1979, Boffeli warns that it would not be a slam-dunk to oust the Milwaukee Bucks owner.

“I don’t know if he’s really serious about it and the bloom has really come off the Tommy Thompson rose,” he said, adding that Thompson “was not very visible in the Cabinet” and that he left the state with a large budget deficit.

“For someone who has this legacy of being the ultimate force in Wisconsin politics, he didn’t really flex much muscle” in the Bush administration, Boffeli said.

If Thompson took on Kohl and lost, he would tarnish his legacy as well, Boffeli added.

Milwaukee-based GOP consultant Todd Robert Murphy said: “No one credible would run against Kohl because Kohl could put $10 million” into his campaign tomorrow.

“He’s a well-liked guy and has a popular family name,” said Murphy, who has also worked for Democrats. “No one has a problem with Herb Kohl. It would be kind of a quixotic quest, so I don’t see Tommy Thompson doing it.”

Thompson really wanted to head up the Department of Homeland Security or the World Health Organization but may end up president of a large Wisconsin-based health care company, Murphy said.

If Thompson takes a pass, as is widely expected, no line has formed to take his place in the Senate race.

Many political watchers note that Republicans may find Kohl harder to beat after Sen. Russ Feingold (D-Wis.), who they thought was the more vulnerable of the duo, handily defeated millionaire business executive Tim Michels (R) in November.

“At this very, very, early stage of the game I kind of see us being in the position we were in in 2000 … when we came up pretty far short against Kohl,” the Republican insider said. “I fear this is where we’re heading this time. People are looking at Feingold’s [success] and saying, ‘I don’t want to mess with it.’”

As for the three Republicans who vied vigorously for the right to challenge Feingold this year, none is likely to try again.

“Michels is the one out there who hasn’t closed the door on making another run,” the source said. “But maybe he would aim lower than U.S. Senate” next time.

While Republicans shy away from the Senate race, jockeying has begun in earnest for the right to take on Doyle, who won only 45 percent of the vote in 2000.

No one has officially jumped in, but Green is considered a sure bet to run.

Green, who was just easily elected to a fourth term, is sitting on a $1.3 million campaign war chest, much of which he can apparently use to run for state office. His former chief of staff, Mark Graul, headed up President Bush’s Wisconsin campaign.

Graul’s efforts on behalf of Bush-Cheney in Wisconsin “was widely seen as preparation for Green to run statewide,” the Republican source said.

Chris Tuttle, Green’s current chief of staff, acknowledged that the Congressman is serious about making the leap.

“Since Election Day, Mark has been taking a serious look at running for governor,” Tuttle said. “He has not yet made a decision but is edging closer to getting into the race.”

However, Green in no way has a lock on the GOP nomination.

Milwaukee County Executive Scott Walker (R) recently held a fundraiser, despite just being re-elected in April, and has begun criticizing Doyle.

Walker also has a larger base to work with than Green and better name recognition.

Milwaukee is the state’s largest population center while Green’s district includes mainly small towns, save Green Bay.

“I know [Green’s] taking a look at it but I think the troops are rallying around Scott Walker and he’s doing a lot of smart early things,” Murphy said.

Another oft-mentioned potential candidate is Wisconsin Assembly Speaker John Gard (R).

Behind the scenes, numerous state lawmakers are lining up to take Green’s seat, though no one officially is running yet.

State Assemblywoman Terri McCormick (R) has already hired a fundraiser in advance of a possible bid. Gard could also be a candidate if he doesn’t run for governor. Also mentioned on the Republican side: state Assemblyman Frank Lasee and state Assemblyman Steve Wieckert.

Democrats who could run for an open 8th district seat include state Sen. Dave Hansen and former Green Bay Mayor Paul Jadin.

Rep. Paul Ryan (R) is often mentioned as a potential gubernatorial or Senate candidate, but so far he has kept a low profile.

“Right now I’m focused on Social Security reform and tax reform. I have no plans to take on Kohl,” Ryan said.

“Herb says he’s running again, I believe he is … if he changes his mind, that’s a different story,” he added, noting the 69-year-old Senator has given no indication that he would.

As for adding his name to the growing list of wannabe governors, Ryan dismissed that notion out of hand.

“I’m not going to run for governor,” he said.

O’Neill, the GOP fundraiser, said Ryan can be forgiven for not wanting to give up a seat on the Ways and Means Committee at a time when he is gaining seniority in Congress. And at 34, Ryan doesn’t have to make the leap soon.

“Everyone believes he has a bright future here in Wisconsin politics and that he’s not always going to be a Congressman,” O’Neill said.