Former Gov. Tommy G. Thompson called for big cuts at all federal agencies, including the Pentagon. And businessman Eric Hovde called for means testing for Social Security.
Businessman Mark Neumann and Assembly Speaker Scott Fitzgerald said they would use their past experience in government to attack the federal deficit.
The four spoke at an event at the Milwaukee Athletic Club, sponsored by Citizens for Responsible Government, also known as CRG Network. They'll face each other in the Aug. 14 primary, with the winner taking on U.S. Rep. Tammy Baldwin (D-Wis.) in November.
Each of the candidates emphasized his conservative credentials and told the luncheon crowd why he had the best background to address everything from the economy to paring the federal deficit.
The sniping between Hovde and Thompson took place after their speeches.
Hovde told reporters at a news conference that the biggest difference between himself and front-runner Thompson is Hovde's superior expertise on the economy and financial markets.
"I think these are issues I can talk about that, quite frankly, Tommy Thompson would have a hard time understanding," said Hovde, who built a fortune in banking, finance and real estate.
Thompson shot back.
"I would say anybody that makes those kind of statements is not very bright," Thompson said. "And I would also say, you know, he doesn't know anything.
"Who's the one that created jobs in Wisconsin? Who's the one that has balanced the budget 14 times? Who's the one that has never taken TARP money or any stimulus money? Me.
"I think Eric Hovde better be more concerned about the money he took and where he got it than worrying about me. I don't worry about him. I don't worry about anybody. I worry just exactly about me."
Hovde, who owns community banks, says that he never received money from the Troubled Asset Relief Program, but that like many stock market investors, some companies in which he's invested received funds from TARP, which bought poorly performing companies in an attempt to help bolster the economy.
Later in a meeting with Journal Sentinel editors and reporters, Hovde said Thompson - like many politicians - lacked an understanding of international finance and the underlying causes of downturns in sectors such as the Internet and real estate industries.
"It's not meant to be demeaning one iota to Gov. Thompson," Hovde said. "I've respected him as an individual. I've respected what he's done. But it's time - instead of having speeches (about) what I did 20 years ago, or say I'm the one whose leading the polls, to come and talk about what he plans to do for the country."
In his luncheon remarks, Thompson emphasized that he's the only politician in Wisconsin who is known by his first name and reminded the group that polls show he has the best chance to beat Baldwin.
"It's a sign of trust," he said. Thompson cited his past accomplishments: welfare reform, starting the Milwaukee Parental Choice Program, signing 91 tax cuts while governor and eliminating gift and inheritance taxes.
After serving as health and human services secretary under President George W. Bush, Thompson moved to the private sector, where he has served on numerous boards and was chairman of Logistics Health Inc. of La Crosse, which he said has created about 1,200 jobs.
Thompson called for big across-the-board spending cuts in the federal government, including military spending.
"I'm running on a balanced budget, cutting every department 5%, reforming the taxes, reforming health care and also making us energy independent," Thompson said during a news conference.
Under his plan, even the Pentagon would be subject to the 5% cut.
"You don't just say . . . the cut. There's a connection there," he said. "That is giving the secretaries the ability, the power to reorganize their departments."
Hovde said the cost of entitlement programs will have to be curtailed to avoid bankrupting the country.
On Social Security, he said those younger than 50 should be required to work at least two years longer to collect benefits. Those younger than 40 should be required to work an additional two years beyond that.
The current retirement age for full benefits is 65 or 66, depending on age.
Hovde also said that for wealthy people, "you are going to have to do some level of means testing for Social Security. If we don't, everyone is going to lose it."
Hovde has put $4 million of his own money into his campaign, his latest campaign finance report shows, while raising slightly more than $350,000 in contributions.
According to the Center for Responsive Politics, Hovde ranks fifth among Senate candidates in giving money to his campaign. The largest self-funding candidate is Republican David Dewhurst of Texas, who has put almost $7 million of personal money into his campaign.
Hovde has spent $3.8 million as of June 30.
In his presentation and later in an interview, Neumann took umbrage with President Barack Obama's recent remark, "If you've got a business, you didn't build that."
"I built my business just like so many people in this room," said Neumann, a home builder. "I find it insulting. What is he talking about? We took the risk, we had the ideas, we were the entrepreneurs who took a chance and employed people and built our businesses from the ground up."
Fitzgerald acknowledged his underdog status. But he believes a low voter turnout in the primary and the negative attacks by the other candidates could work to his advantage.
He said his leadership in the Assembly during the tumultuous days at the Capitol in 2011 showed that he has the leadership to address problems in Washington.
"With me, you don't have to ask whether I have political courage," Fitzgerald said. "I just showed it to you."Craig Gilbert of the Journal Sentinel staff contributed to this report.