Columbus business executive Tony Raimondo, a longtime Republican, said Monday that he was filing federal paperwork to begin his campaign for the Democratic nomination to the U.S. Senate.

"I pledge to be a public servant -- not a professional politician," Raimondo said. "I will bring my real world business experience to Washington and fight against the career politicians who unwittingly stifle innovation, economic opportunity and development."

When he joined the Democrats, Raimondo said Republican Mike Johanns' entry into the race convinced him he couldn't raise the money to win the GOP primary.

"The pundits say this is an uphill battle; that the special interests in Washington have lined up behind my Republican opponent. That is true.

"But I have faced tough battles in my life," Raimondo said as he recounted how he had helped lead a bankrupt Behlen Mfg. Co. back to prosperity. He's chairman of Behlen.

"I want to take that same 'can-do' spirit to Washington," he said. "I want to work to change the broken system in Washington, end the partisan bickering and get the work of the people done."

Under federal rules, once a candidate either raises $5,000 or spends $5,000, he or she must file a statement of organization or a statement of candidacy. Raimondo was filing both, said campaign spokesman Paul Johnson.

Raimondo's formal, fly-around-the-state announcement will come later this month. "We expect it in three or four weeks," Johnson said, but that schedule depends on the late winter weather.

In the Democratic primary, so far Raimondo faces only Larry Marvin of Fremont, who has said he intends to be "the David who defeats Goliath" in the campaign to replace Republican Chuck Hagel, who isn't seeking a third U.S. Senate term.

Another prominent Democrat who has said he might run is Scott Kleeb, who lost the 2006 3rd District House race to Adrian Smith, who recently declared that he'll run for re-election.

Schuyler businessman Pat Flynn remains in the Republican race against Johanns, a former Nebraska governor. Johanns resigned as President Bush's agriculture secretary to return to Nebraska for the Senate race.

Steve Larrick is the Green Party candidate.

Raimondo said he's running in part because partisan gridlock has "overtaken common sense" and that it's time to return to the concept of a citizen legislator, one who is not bound by party or special interests.

He also wants to help America's middle class, which he said "is being squeezed" by health care and energy costs and higher taxes and food prices.

"Our national debt is a disgrace," Raimondo said. "Fiscal discipline has been thrown out the window along with our domestic priorities like supporting agriculture, energy independence and responding to natural disasters at home."