Former California Gov. Edmund G. "Jerry" Brown Jr. always has been noted for his vision, but it is difficult to imagine that even he could have dreamed this one up:

Two-term governor returns from worldwide search for self to run for chairman of party he once spurned.Believe it.

The man they called "Gov. Moonbeam" is back.

Brown, at one time considered one of the nation's most promising politicians, has launched a massive campaign for the unlikely position of chairman of the California Democratic Party.

"Yes, it's very unusual. I haven't been able to find any other governor in the history of this country who's done this," Brown said. "But I like to do things that are unusual."

The "Boy Governor," as he once was known, has been working tirelessly to win the support of the 2,800 party delegates who will elect a new chairman to a four-year term Feb. 11. Brown faces a single challenger in the race, Steven Westly, a 32-year-old venture capitalist who serves as vice chairman of the party.

Brown's relentless pursuit of the somewhat paltry post represents an about-face for a man who as governor shunned party regulars and refused to kiss babies, sign autographs or cut ribbons.

In a lengthy essay - a sort of self-analysis - in The Sacramento Bee in December, Brown acknowledged: "One thing I did not do is build a strong Democratic Party or even an enduring political organization. I knew where I was going, but too often I was going there by myself.

"In the frenetic effort to introduce new ideas and shape a different constituency, I forgot about the basic building block of any powerful institution: shared effort, shared philosophy and caring," Brown wrote. "That is a painful truth I now understand."

Still, in some quarters, the former governor's motives are suspect. Many believe the two-time candidate for U.S. president is attempting to use the party as a jumping block to higher office - the U.S. Senate or the presidency, perhaps.

While he has won the loyalty of the party elite such as Assembly Speaker Willie Brown and U.S. Sen. Alan Cranston, there are others who rue the day Jerry Brown came back to haunt them.

Many remember him as the man who once dated singer Linda Ronstadt and was soft on crime and indecisive in crisis. They sum him up in short order: Rose Bird and Medfly.

It was Brown who appointed the liberal Rose Elizabeth Bird to be chief justice of the state Supreme Court though she had no judicial experience, and it was Brown who delayed the aerial spraying of Santa Clara County even as it was overrun with destructive Mediterranean fruit flies in 1980. Furthermore, critics say Brown is a poor manager who pays little attention to detail and organization.

"He is the wrong person at the wrong time in the wrong place," according to Assemblyman Richard Katz, a Democrat from a Los Angeles suburb who chairs the Assembly's transportation committee. "Jerry Brown is history and it's better left that way. Not only is he a negative symbol, but his re-entry clouds the whole picture as we look toward 1990."

Some Democrats are concerned that Brown's controversial re-emergence could hurt their chances of electing a Democratic governor in 1990, a year that promises some dramatic changes in the state's political lineup as a result of Gov. George Deukmejian's recent decision not to seek a third term.

Brown was the last Democrat to serve as governor of California, a position he held from 1975 to 1983, when he left politics after a stinging defeat in a race for U.S. Senate.

Retired as governor of the nation's most populous state at the age of 44, Brown embarked on a worldwide odyssey that took him to Japan, where he studied Zen Buddhism, and to India, where he tended to the dying and the destitute with Mother Teresa.

"There was much, much more that I had to understand," the former Jesuit seminarian said about his return to private life. "It was time to stop what I was doing and look inward." His search for perspective, as Brown has called his wanderings, lasted six years.

Brown, whose father served two terms as California governor, said the future of the Democratic party lies in its use of direct mail, telemarketing and door-to-door contacts to build a financial and electoral base.

Night after night, Brown has been packing libraries, community halls and private homes with party faithful who have turned out to listen to his message, but he injected controversy into an otherwise ho-hum election almost as soon as he announced his intentions. Among other things, he rented an apartment in San Francisco to meet a party requirement that the next chairman come from Northern California. Brown had been living in Los Angeles.

"That's not playing by the rules," said opponent Westly, who had been heir apparent until Brown showed up. "Now is not the time for Jerry Brown to come back. He is a lightning rod for negative publicity and he makes it tougher for us to attract mainstream Democrats. He's not a manager, even by his own admission and rules. He doesn't play by them."

The only formal poll on the election suggests the race is still a contest.

A survey of 216 party delegates conducted by The San Francisco Poll on Jan. 10-11 indicated 24.5 percent favored Brown and 19.9 percent supported Westly, leaving the rest uncommitted.

California Republicans are celebrating Brown's comeback. "It recalls a lot of unpopular politics he pursued as governor. We as Republicans are always happy to have these issues dredged up again," said state GOP chairman Robert Naylor. "It's not fatal all by itself, but it's a nice reminder."

Brown loyalists believe their leader will prod the party organization into action. Brown himself calls it the "anti-party party." Voter registration in the party is the lowest it's been in 50 years.