DAVENPORT, IOWA, SEPT. 23 -- Sen. Joseph R. Biden Jr.'s former rivals for the Democratic presidential nomination gathered for a debate tonight on urban issues, paid respects to a fallen competitor and pondered the meaning of his withdrawal.

"When this campaign began, I'll be honest, I wasn't very warm toward Joe Biden," former Arizona governor Bruce Babbitt said shortly before the forum sponsored by the League of Iowa Municipalities. "But to my utter surprise, I really came to like him and his family.

"I called him Friday and I told him, 'Don't withdraw. Ride it out.' Obviously, it's a very personal decision."

Jesse L. Jackson said he made three separate calls, mostly to offer consolation, to Biden since stories about the Delaware Democrat's plagiarism and misstatements about his academic record began appearing 10 days ago. "I told him I know the hurt and the inner pain, the sense of your whole life going up in smoke," Jackson said. "When a firestorm like this hits, there is almost no way to handle it. If you back up, the fire engulfs you; if you move forward, it engulfs you."

Jackson said he thought Biden had made a politically wise decision. "He took a look at his options and decided how to best manage the damage. The first option was the Bork hearings, the second option was to protect his Senate seat. Those are birds in hand. The third option was the presidency. At his age, that's a bird in the bush. The bird in the bush is the most expendable."

Jackson said Biden will be missed in the campaign because "he had the ability to inspire people, to get them involved."

Massachusetts Gov. Michael S. Dukakis said he was "very saddened by all this. I like Joe." The other contenders -- Rep. Richard A. Gephardt (Mo.), Sens. Paul Simon (Ill.) and Albert Gore Jr. (Tenn.) -- also spoke glowingly of Biden in their formal opening statements.

Rep. Patricia Schroeder (Colo.), who was slated to participate, canceled just hours before the forum, citing last-minute schedule difficulties. She will announce next week whether she intends to seek the nomination.

"She missed a golden opportunity tonight," Iowa Democratic Party spokesman Phil Roeder said, noting that with Biden suddenly out, party activists here will be looking for a new candidate.

The debate was subdued as candidates answered questions about industrial development bonds, infrastructure repairs and hazardous waste disposal. All six candidates advocated airline re-regulation, citing the need for antitrust enforcement, more rigorous safety standards and restoration of service to small towns.

A few broad areas of disagreement emerged. Dukakis and Jackson each called for shifting federal funds away from the Defense Department and toward urban needs. Jackson kidded Dukakis about being a new recruit to that point of view, prompting Dukakis to reply that it has been a concern of his "for the past 20 years."

Gore said, however, that it is unrealistic to take deep cuts in military spending. Babbitt agreed, and called instead for strict priorities in domestic spending. "I'll tell you what my priorities aren't," Babbitt said, naming general revenue sharing and federal funding for infrastructure.

Gephardt called for a focus on "people" rather than buildings. He chided Simon for voting against the tax reform bill last year, which, Gephardt said, eliminated the potential for abuse in industrial development bonds.

Simon, calling his vote against the tax bill "one of the best I have ever made," said additional revenues should come from a new 6 cent-a-gallon gasoline tax. A third of the money raised would be used for federal highways, a third for state and local roads and a third for mass transit.

Jackson proposed that 10 percent of the $600 billion in pension funds held by public employe unions be invested in infrastructure repair and housing construction, with the federal government guaranteeing the investments.

Before and after the debate, Biden's withdrawal from the race was the focus of most reporters' inquiries. Several of the candidates seemed at a loss to judge whether the punishment fit the crime in this instance, and whether the news media have grown overzealous in probing the faults of presidential candidates.

"The accumulation of incidents led to a snowball effect," Gore said. "If it had been just one episode alone, it would have been very different."

"The individual incidents, taken in isolation, clearly were not cause for this kind of reaction," said Babbitt. "When you add it all up, it's a pattern of carelessness verging on bad judgment . . . . Clearly, he was caught in a crosscurrent of changing judgment criterion."