The "children of the 1960s" came together here this weekend to discuss their future in the chilly, grown-up politics of Proposition 13. Like children of other times, they found themselves uncertain and adrift in a world they never made.

The National Conference on Alternative State and Local Policies - led and organized by some of the prominent young radical political activists of the 1960s - met here for three days under the shadow of Jarvis-Gann.

Now scattered in government offices, community organizations and public-interest groups from Washington, D.C., to Alaska, the 650 veterans of the peace and civil rights movements and the radical politics of the 1960s saw their fourth annual reunion marred by the anxieties they all feel about the sudden lurch rightward of the people they have spent their lives trying to organize.

"Is our time past" asked Tom Hayden, the organizer of Students for a Democratic Society and a Chicago 7 defendant. He and others said it was not possible they were relics while told were of the John Birch Society taking over a black community organization in Atlanta and blue-collar majorities voting against the rights of homosexuals and other minorities.

As self-proclaimed "populists," they worried that their enemies on the right have mobilized the masses through a tax protest they somehow felt should have belonged to them.

"It's in the nature of American populism to give mixed blessings," mused Hayden, who now operates a left-wing think tank and political movement in California.

Talking of Jarvis-Gann, last month's property tax rollback vote in California, which he said marked "the death of the New Deal," Hayden capsulized the ambivalence that was so evident at this conclave on the Concordia Colege campus.

"It is, in many respects, a legitimate grassproots populist revolt against the stupidity of government," he said. "But it clearly favors the large land owners and property owners. It really put us in a kind of a bind."

Sam Brown, an antiwar organizer who heads the Action agency for volunteer social projects in the Carter administration, said that Proposition 13 showed "American liberalism is out of touch with the nation's mood. People are tired of massive, anonymous megaprograms that provide visible benefits only to professional bureaucrafts. The property tax is no longer a viable instrument of public finance."

But he, too, said Proposition 13 had to be recognized as part of an attack on "the poor, the black and the brown."

And Byron Dorgan, the North Dakota tax commissioner, said Proposition 13 was "a vote for latent prejudice . . . but still a legitimate protest against waste by working people."

Behind the confused reaction was the sense by these activists of the 1960s and their old enemies of the poltical right had outmaneuvered them and gotten closer to the people, at least on the issue of taxes and government waste.

Many of the activists are, in fact, busy climbing the first rungs on the ladder to power. Brown led a contingent of perhaps two dozen junior Carter administration appointees. Others here hold city and state elective office and many are in key staff jobs in local government.

But most are still "on the outside," working in community groups and environmental and energy coalitions, and doing the same tedious tasks of organizing that they began a decade or more ago.

Their reaction to the California initiative took three different forms.

Big-city politicians, especially those whose constituents are poor, said the new era of austerity in city budgets means Washington must do more, not less, to redistribute jobs and income to needy people.

State Rep. Barney Frank of Massachusetts, New York City Council President Carol Bellamy and Hartford City Council President Nick Carbone all said the need to direct more money to the poor was greater in the era of Jarvis-Gann.

Frank said the talk that "you can't solve problems by throwing money at them is the silliest thing I have ever heard. The poor need money, and so do poor neighborhoods. I'm not ashamed to have Boston be the ward of the federal government."

A second group, including many of the community organizers, was much less hopeful of relief from Washington or progressive leadership from national officials. "President Carter has been a real political disappointment," said Lee Webb, the executive director of this conference, which serves as a clearinghouse for activists across the country.

Webb, a former SDS organizer and local official in Vermont, said that only "a new generation of public officials committed to using the resources of state and local government to meet the full range of human needs can assure that Jarvis-Gann is not the wave of a conservative future."

The third group is composed of those who see in the new mood a chance to mobilize support for their long-term goal of reducing corporate power in America or socializing the basic industries.

"If business does not give back some of the windfall money it has gained from Proposition 13," Hayden said, "business will face a Proposition 13 of its own in a year. If the public can vote to lower taxes, it can vote to lower profits as well."

Economists Gar Alperovitz said progressives (the favorite self-label for the radicals, socialists and left-wing Democrats mixing here) "made a mistake in abandoning the issue of inflation. We should be attacking the rising prices of food, housing, energy and health care . . . and focus that anger on Exxon, agribusiness, the big banks and developers, and the health-care establishment."

Fred Bronfman, a colleague of Hayden in California, said that if the tax revolt cuts off public funds for social programs, new sources of capital should be found by commandeering private pools of capital. He said proposed legislation in California to require utilities to make low-interest loans for solar energy installations was an example of the "capital wars" that will have to be fought in the 1980s.

If the "progressives" were divided by their reaction to Proposition 13, they were equally ill at ease with the Carter administration. References to the president execept those from his appointees ranged from the mildly critical to the caustic.

Warning that conservatives would have "a tremendous opportunity" to ride to the White House in 1980 in the "distorted populism of Jarvis-Gann," Hayden said he was worried that the administration "is disintegrating." He gave Carter a year to improve his political standing, but said that if he could not, "it is inevitable there will be Democratic primary opposition and then we will have to make a very serious decision, as serious as we made in 1967."

Brown, one of the leaders of the dump-Johnson movement a decade ago, said that, as a Carter appointee, he hoped Democrats had discovered "you can't run against an incumbent president of your own party and hope to win. I'm not sure it was a mistake in the 1960s, but it's a pattern we cannot afford to continue."

Over and over, speakers at the panels bemoaned the lack of a developed "progressive" philosophy on economics, foreign policy or political reform.

The lament for that lost consensus was expressed most plaintively by Belamy, the former Peace Corps volunteer who now is the No. 2 official in the New York City government. "A decade ago," she said, "the key issues and goals were clear . . . and our coalition was strong . . . There were scenes of horror in 1968, but there was also a kind of special certainty. We knew our goals, we knew our friends, and we knew our enemies. I wonder if we will ever be as certain again."