BOZEMAN (AP) -- Three candidates for the Democratic nomination for the U.S. Senate who debated here were critical of the war in Iraq, said funding education is important and agreed Sen. Conrad Burns needs to be replaced.

"Conrad Burns is an auctioneer," Senate President Jon Tester said, referring to Burns' previous career. "He has continually decided to sell his seat to the highest bidder."

Democrats have keyed on Burns' links to disgraced Washington lobbyist Jack Abramoff, the focus of a Justice Department investigation into possible congressional influence-peddling.

Tester, John Morrison and Paul Richards are all seeking their party's nomination to run for Burns' seat. The primary election is June 6.

The candidates are working to define themselves to a public that doesn't know much about them, with Tester and Morrison citing their experience in public office.

Polls have shown Morrison, the state auditor, with the greatest name recognition among the three, although Tester, the president of the state Senate, is popular with many party insiders. Richards, a former state lawmaker from Boulder, is considered a long-shot to win the nomination.

All three candidates were critical of the war in Iraq, with Morrison saying the troops need to be protected and there should be no permanent U.S. military bases in Iraq. He said Iraq needs its own national oil company.

Tester and Richards favored getting American troops out of Iraq immediately.

All three favored developing alternative fuels as a way of lessening dependence on oil from the Middle East.

On health care, Morrison spoke of his efforts to promote tax breaks and other measures that helped small businesses provide health insurance for their employers, while Tester said he pushed measures in the Senate to help people pay for prescription drugs. Richards said he favors a single-payer national health care system such as the one in Canada.

All said higher education was important in allowing Montana to provide a skilled workforce that could attract more business to the state.

Morrison said higher education should be a priority as Congress doles out federal money. Tester called for more federally subsidized student loans while Richards said all higher education should be free.

The debate, held at Montana State University, was sponsored by the MSU College Democrats and the Gallatin County Democrats and they asked the first six questions. Ethics came up when members of the crowd were able to query the candidates.

One asked what it would take to eliminate the influence of money and lobbying in Washington, D.C.

Morrison said the "revolving door" of political staffers going into lobbying needs to be closed and suggested aggressively prosecuting lawmakers who trade their votes for money.

Tester said he has come out with his own set of ethics guidelines that he said his office will implement if elected.

Richards said public financing of campaigns would clean up the system.

Robert Candee of Richey and Kenneth Marcure of Missoula are also seeking the Democratic nomination, but were not at the debate.