Vice President Mondale, Sen. Edward M. Kennedy and California Gov. Edmund G. (Jerry) Brown Jr. traded quips and arguments tonight in the closet approximation of a Democratic presidential candidates' debate of the 1980 political year.

The three men were guests at a Black Hawk County Democratic dinner nine days before the Iowa caucuses, which start the convention-delegate selection process.

Although the site in a United Auto Workers hall favored Kennedy, the endorsed candidate of the UAW, Mondale and Brown both found cheering sections that rivaled that of the Massachusetts senator.

Brown and Kennedy joined forces to call on President Carter, who has avoided any overt campaign appearances, to come out of the White House and debate the issues directly with them.

Their demands that Carter defend his own record drew probably the loudest applause of the night from the 650 persons jammed into the union hall.

But Mondale spared no rhetoric in defending the absent president as a man who is "compassionate, honest, energetic and effective."

Mondale asserted that the best proof of Carter's character was his decision to impose a partial grain embargo against the Soviet Union to protest its invasion of Afghanistan.

"I knew what that would mean politically," Mondale said, "and so did the president. We are farm-state politicians. But we knew this was the one thing that would deliver a message with a sting."

But Kennedy rejected the contention that the embargo would hurt the Soviets and repeated his contention that the real victim would likely be the American farmer -- a view that Brown implicity endorsed.

The Californian, unconventional as always, began the evening by saying he would rather answer questions than make a speech. Kennedy and Mondale both saved time for questions, but repeated the essence of their Iowa campaign speeches as well.

There was no sign of animosity among the three men, though there had been prolonged bickering among their staff members, the format and even the location of the meeting.

When Brown told a questioner he would welcome any suggestions about "what we can do to get President Carter to debate," Kennedy immediately leaped to his feet to applaud.

The senator took a good-natured poke at Mondale at the outset of his remarks. In an allusion to Mondale's implication earlier this week that those who criticized with the national interest than with their political campaigns. Kennedy gave the vice-president a New England Patriots football jersey.

"I present this as one good patriot to another." Kennedy said.

Mondale, in turn, kidded Kennedy about his promise to save the long-defunct Wabush railroad and about his garbled reference early in the Iowa campaign to "farm families."

Perhaps the biggest laugh of the evening came when the master of ceremonies told Brown that there was one question everyone wanted to ask him. Picking up the cue, a member of the audience shouted, "Where's Linda?" -- a reference to Brown's frequent companion, singer Linda Ronstadt.

Brown who seemed amused looked around to see who had shouted the question, and Kennedy pointed an accusing thumb in Mondale's direction.

In the more serious parts of their hour-long speeches, the two challengers repeated their basic positions on defense and foreign policy, while Mondale defended the Carter record.

Brown said the Carter administration lacks "a coherent foreign policy," and said the United States should seek both a NATO summit meeting and a high-level conference with "our Islamic friends" to develop "a coherent response" to both the Iranian hostage situation and the Soviet agression in Afghanistan.

But he opposed higher defense spending by the United States, arguing that the United States should instead call on Germany and Japan to expand their military budgets, so that America can invest in economic "reindustrialization."

Kennedy said that American foreign policy "should not be made on the basis of trusting the Soviet Union," and called for "beefing up" conventional forces for rapid deployment. But like Brown, he expressed skepticism on the need for any major new strategic systems.

Mondale, noting the criticism from Carter's two challengers, boasted that the Egyptian-Israeli summit conference, the ratification of the Panama Canal treaties and other accomplishments demonstrated the success of Carter's foreign policy. "His handling of the Iranian hostage situation has been masterful," Mondale said.