While being careful to say he didn't believe Democratic U.S. Sen. Frank Lautenberg was unethical, GOP Senate challenger Richard Zimmer said in a radio debate last night that the senator was part of a broken system "that results in the fact that many members of Congress are now behind bars for selling the power that they have over federal funds."

Zimmer said Lautenberg received millions in campaign funds from lobbyists and lawyers representing special interests and had a lobbying firm arrange to "scalp" tickets for a summer fund-raising event at a Bruce Springsteen concert this summer.

"We have got to stop this system where members [of Congress] are marinating in special interest money," Zimmer said.

To that Lautenberg had an audible sneer in his voice as he told listeners of debate host New Jersey 101.5 FM that Zimmer had worked as a Washington lobbyist.

"No one's going to know it better than Dick Zimmer. He was a lobbyist," Lautenberg said scornfully. "No one can say after my service of 24 years in the United States Senate and chairman of a public company that Frank Lautenberg ever gave away anything in exchange for something else. If there's anything on the record that tells you differently, the record is wrong."

Zimmer is on leave from the Washington law firm Gibson Dunn & Crutcher, where he worked as a registered lobbyist.

He said he never participated in "wining and dining" members of Congress as a lobbyist and that his work relied on his knowledge of legislation and agencies rather than whom he knew. He added that while a member of Congress in the 1990s, he only once went to a restaurant in Washington with New Jersey restaurant owners.

"I did not participate in that type of thing. I don't enjoy it. I'd rather be home with my wife," he said.

The spirited hour-long debate was the first public encounter between the two candidates in the roll-up to Election Day. Lautenberg has declined invitations for other forums and debates, opting instead to debate Zimmer last night on the radio and Sunday on NJN.

That hasn't helped the underfunded Zimmer, who has tried to break through to voters in this race.

But last night the two had at it over taxes, immigration, government spending and the swelling national deficit.

With almost every answer, Zimmer laid into Lautenberg for votes the senator made during his career in the Senate, ranging from his vote on a bill granting illegal immigrants amnesty to funding a rain forest in Iowa.

Lautenberg did not explain the Iowan rain forest vote but said he believed "we need comprehensive immigration reform."

To curb government spending, Lautenberg noted that he fought for the balanced budget amendment during the Clinton administration but added "Dick Zimmer's party came in and blew the lid off the deficit."

Zimmer retorted: "I've got news for you: On Jan. 20, George W. Bush will no longer be president."

Lautenberg pledged to seek additional federal money for New Jersey to help state and local governments avoid deficits. Zimmer said the best way to ease the financial crisis is "to elect somebody who makes sure we don't spend one dollar more than is absolutely necessary."

Lautenberg prides himself in bringing home money for mass transit, highways and other public projects. Zimmer is opposed to pork barrel spending, including money that would come to New Jersey.

The son of a mailcarrier and encyclopedia saleswoman, Zimmer, 64, has had a long political career. A former state legislator elected to Congress in 1990, Zimmer left the House for an unsuccessful run against former Democratic U.S. Sen. Robert Torricelli in 1996. A Yale University-educated attorney, Zimmer worked as a lobbyist in Washington, traveling home to Delaware Township on the weekends. He remained active in civic affairs and kept his interest in politics.

Paterson-born Lautenberg, 84, a cofounder of the payroll company ADP, is a self-made multi-millionaire who used his personal fortune to launch his political career in 1982, winning a tough race for Senate. He retired in 2000 but came back to politics in 2002 after Torricelli's campaign imploded in an ethics scandal.

Contact staff writer Cynthia Burton at 856-779-3858 or cburton@phillynews.com.