Tom Horner, public affairs guru and former Republican staffer, said Monday that he'll soon file papers to allow him to raise cash for an Independence Party run for governor.

Horner said he began thinking about running when he believed former Sen. Norm Coleman would run as a Republican and Coleman's decision not to run is unrelated to his decision to move forward.

"When I first started making the calculation, I actually thought Sen. Coleman would get into the race," Horner said.

For Horner, the decision to file a campaign committee as an Independence Party candidate means he is leaving the Republican Party, which had been his longtime home.

"I believe there is an opportunity for somebody from the middle to come in and present a different option," Horner said.

Horner isn't yet all in the race. He referred to his coming campaign finance filing as the creation of an exploratory committee. But, as he knows, Minnesota doesn't make any distinction between an exploratory committee and a campaign committee. He said he will file his paperwork with the campaign finance board, "with the intention, frankly, of continuing to move forward."

The committee will allow him to find out if the support he believes is out there for his run translates into dollars for his campaign.

"That's the next big question that has to be tested," Horner said. While he's received encouragement from folks, the question is: "Are they willing to back that up with the kind of contributions it will take to run a credible campaign?"

Horner's decision to continue with a run means that he's losing at least one gig.

Horner, a longtime staffer to former U.S. Sen. Dave Durenberger, has long been a Republican pundit for Minnesota Public Radio. His was last on the air, reviewing the year in politics, on Dec. 28.