Like Ronald Reagan and Walter F. Mondale, David Bergland is worried about the budget deficit and the national debt. Unlike the other presidential contenders, Bergland has a plan to eliminate these problems forever his first year in the White House.

"We have to face the reality that the government is a bankrupt," says Bergland, a 49-year-old California lawyer who is the 1984 standard-bearer for the Libertarians, the nation's third-largest political party.

"And what do you do with a bankrupt? You liquidate its assets, pay the debt and try to keep going at a smaller scale."

And so a Libertarian administration would sell the national parks and forests, the Federal Triangle, the service academies, the Hoover Dam, the gold in Fort Knox, all overseas military bases and just about every other government asset.

It would use the income to pay debts and make a lump-sum final payment to all Social Security beneficiaries so that program could be shut down as well.

This would leave the government a shadow of its present self, but that is precisely what Bergland is demanding as he stumps the country trying to win converts to his call for a total free-market economy and a totally noninterventionist foreign policy.

The Libertarians see government as an inherently wasteful and inefficient mechanism that invariably tramples on individual rights.

Accordingly, Bergland wants to restrict it to two basic tasks: the police function of protecting personal liberties and property, and the military function of guarding against foreign invasion.

"Walter Mondale says he wants to reduce the budget deficit by two-thirds over a four-year period," Bergland told a polite but somewhat skeptical college audience here. "I'm a little different. I want to reduce the whole budget by two-thirds."

During his first term as president, Bergland said, he would like to reduce the federal budget, now about $950 billion, to $200 billion.

If that were done, he says, it would be possible to abolish another government institution that Libertarians deplore: the Internal Revenue Service.

"Taxation is legalized theft, pure and simple," Bergland says. He would prefer to finance his stripped-down government through an endowment fund financed by sale of military academies and installations, or through a "national defense lottery."

Bergland, a slim, natty grandfather who looks something like an older Johnny Carson, set forth these ideas here in unyielding tones, refusing to concede even the smallest point when a member of the audience challenged the Libertarian creed.

His ideological fervor has made him the darling of the purists in the 13-year-old party, where the description "radical" is high praise.

But Bergland also has been the target of harsh criticism from some more "pragmatic" elements of his party, particularly those at the Cato Institute, a Washington-based think tank. They say he has failed to reach out and attract new voters the way Ed Clark, the party's 1980 presidential candidate, did.

Clark, who proposed a phased-in transition to the Libertarian state and put together "white papers" on central issues, received generally sympathetic news coverage and won just under a million votes.

It is doubtful that Bergland will do as well.

Clark had the advantage of having a wealthy running mate, David Koch, who put $2 million of his own money into the 1980 campaign.

Bergland says he hopes to raise $1 million this year, but is well short of his goal.

One key result of this financial gap is that Bergland did not match Clark's feat of being listed on all 50 state ballots, a difficult and expensive task for third parties when Democrats and Republicans write the ballot-access laws.

With some litigation still pending, Bergland says he expects to be listed on 42 ballots, including those in Maryland and the District of Columbia.

Clark was able to run national television ads in 1980. This year, Bergland has made two hard-hitting ads -- one on personal freedom, the other on nuclear war -- but cannot afford to show them.

And so the candidate has spent the campaign year slogging from campus to Kiwanis Club, from radio interview to editorial-board inquisition, trying to spread what he calls "the rather remarkable proposition that your life and your body belong to you."

He gives a resigned smile when interviewers ask about "the three Ps" -- prostitution, pornography and pot -- which would be legal under Libertarian rule.

But the Libertarian position does provide an easy answer to some questions that mainstream politicians stumble over.

Ask Bergland about prayer in the public schools, for example, and he will tell you that "prayer in school is a problem only because government operates the schools. We should separate school and state for the same reasons we separate church and state."

Immigration law becomes equally simple because government has no right to control it, Bergland says. "Human beings have the right to travel and seek opportunity wherever they desire."

The same principle applies to abortion. "Government shouldn't prohibit it or pay for it. Your body is up to you," Bergland says.

Bergland says his strongest issue has been peace. "It has a powerful, powerful attraction to voters," he says.

He does not mince words about President Reagan's foreign policy. "We should stop pouring American blood and treasure down ratholes in Grenada, Lebanon and El Salvador," Bergland says.

"The present U.S. military buildup is robbing Americans blind and . . . creating tempting targets that invite an attack on our homeland."

"The basic rule is that our government shouldn't interfere with life in other countries," he says. "And for that matter, it shouldn't interfere with life in this country, either."