MADISON, Wis. -

Democratic state Sen. Tim Cullen is bowing out of the governor's race, saying he can't raise the money to compete with better-known opponents.

Cullen had been saying for months that he would run for the Democratic nomination to challenge Gov. Scott Walker if a recall election is called.

But on Wednesday he said that it's too big of a job with not enough time for fundraising.

"I was not getting a lot of groups telling me they would support me in the primary, and I just don't have a whole lot of rich friends," Cullen said.

Cullen said no one asked him to step aside and that he had approached some state unions for support.

"I would say that the general reaction I got, not from all of them but particularly the public ones, was sort of respectful indifference," Cullen sad.

Cullen is a moderate Democrat from Janesville who has been in the Senate since 2010. The 67-year-old previously served in the Senate from 1974 to 1986 before he left to become secretary of the state Department of Health and Human Services under Republican Gov. Tommy Thompson.

He later worked for nearly 20 years as an insurance company executive.

Cullen's decision leaves former Dane County Executive Kathleen Falk as the only announced Democrat.

Falk said she has been seeing support in her bid for the Democratic nomination.

"(There's been) respectful enthusiasm, and because I, as a county executive, worked every day with eight unions, I was fair, I was strong and I was respectful," Falk said.

But there are other Democrats sill considering a run, such as Sen. Kathleen Vinehout.

"I really don't think that labor has lined up behind any one candidate, and I think labor is probably doing what the rest of the Democrats are doing, which is sorting out who is in and who is out and who is going to be the best person to take on Scott Walker," Vinehout said.

Secretary of State Doug La Follette is also considering joining the race.

"I want to make sure that we turn the state back to the people. That means a new governor, and if that is Doug La Follette, fine. If it isn't, I don't need to be governor to fulfill my life," La Follette said.

But Cullen said being the candidate that appeals to all may not be so easy. He said he wanted to bring state together but realized the next governor will be in a terrible position to do that.

"I came to Madison as a centrist and discovered that there was no center," Cullen said.

And there are other candidates still considering a run, including Milwaukee Mayor Tom Barrett. Barrett told WisPolitics.com on Wednesday that he is currently focused on his mayoral race.

Cullen said he wouldn't endorse any potential candidates but would ultimately support the nominee. He said that all of the Democrats who have been mentioned as possible candidates "are good people with solid Wisconsin values."

Cullen said that at this point he plans to seek re-election to the Senate in 2014.

"I am re-energized to focus my efforts as a state Senator on working for more bipartisanship and civility in the state Legislature and Wisconsin as a whole," Cullen said. "Continuing to try to deliver that message in what will be the most angry, partisan race in Wisconsin history would have been impossible. Many people in this building love this political war, but the majority of the people outside of this building want no war, they want us to work together. As a state senator, I intend to accomplish what I have concluded that the winner of this election will not be able to do."