hey met on the sunny UCLA campus in Westwood, learned to use targeted mailings as political weapons, and are backed by affluent and generous West Los Angelenos.

The new musketeers of California politics have ridden into Washington.

Call them the Waxman-Berman bunch. They do not like being called a machine, yet they terrify Republicans--and on occasion fellow Democrats--with the motto of their leader: "Each one helps one," meaning that each of them tries to increase their number by helping like-minded candidates.

Those who have watched their operations in the shingled subdivisions of the San Fernando Valley and the stuccoed barrios of East Los Angeles say California politics may never be the same.

In appearance, California's three leading musketeers seem neither dashing nor menacing: short, mustachioed Rep. Henry A. Waxman, 43; curly-haired, hard-working Rep. Howard L. Berman, 42; and Berman's brother, Michael, 36, a rumpled genius who works behind the scenes here in a perpetual cloud of cigarette smoke.

But these three former UCLA Young Democrats turned friendship, liberalism, pro-Israeli zeal and a talent for untelevised campaigning into a remarkable electoral triumph last year.

They helped elect six new Democrats, five from southern California, to the House of Representatives. California's net gain of six House Democrats was one fourth of the Democratic gain nationally.

The new southern California members are Howard Berman, Mel Levine, 39, a West Los Angeles attorney and skilled fund-raiser, Latino leaders Esteban E. Torres, 53, and Matthew G. Martinez, 54, and Jim Bates, 41, a former San Diego County supervisor. The sixth is Richard H. Lehman, whose district is near Fresno.

They are joined in the House by three other like-minded, mutually supportive California Democrats--Rep. Julian C. Dixon of Culver City, a two-term member and close ally of Waxman, and freshman Reps. Douglas H. Bosco and Barbara Boxer from northern California. A potential addition is Sala Burton, the widow of Rep. Phillip Burton, the group's mentor and ally. She is favored to win her husband's seat in a special election this summer.

Although the group has no real leader, its most influential member is probably Waxman, who with Burton's death becomes the most formidable Californian in the House. His group of friends and allies outnumbers the total delegations of many states, and last year he dispensed about $100,000 in campaign funds to about 30 other House, Senate and gubernatorial candidates around the country.

Waxman's technique of encouraging established liberal legislators to give money and staff help to attractive but struggling liberal candidates was developed when he was first elected to the California assembly in 1968 and found Democrats in a minority.

The "each one helps one" system began, Waxman said, because "we didn't have a party structure at hand."

Even Democrats brushed aside in the group's upward climb choose their words carefully when asked about the Waxman-Berman bunch.

Wallace Albertson, a long-time liberal activist and widow of actor Jack Albertson, lost a 1980 state assembly race to former Waxman aide Burt Margolin, whose campaign was master-minded by Michael Berman. To this day she bristles at the memory of Margolin's campaign attacks, which suggested that she was anti-Semitic (in a heavily Jewish district) for not objecting to one liberal group's call for Soviet participation in the Middle East peace talks.

"I think that power corrupts, finally," she said. "I think I see areas in which--" and she paused. "I'm not willing to go much further. By and large, they're good legislators, and we would be on the same side in many instances."

Most bitterness and suspicion aimed at the group bypasses the skillful, genial Waxman and focuses on the Berman brothers.

Howard Berman caused a painful split in the California Democratic Party in 1979 when he tried to replace Leo McCarthy, now lieutenant governor, as speaker of the state assembly. At the time, Berman was McCarthy's closest lieutenant.

Berman said he thought McCarthy's "complacency" would hurt the party's ability to have its way in the assembly.

Michael Berman was not yet 21, and could not vote, when he managed Waxman's first assembly campaign. He is a short, somewhat pudgy chain-smoker who speaks in sudden quick bursts. Friends and enemies alike call him a genius, with an encyclopedic knowledge of the boundaries of California assembly districts and census tracts and why they were drawn that way.

"I was prepared to thoroughly dislike him," said one Los Angeles political operative. "But how can you dislike someone who is that smart?"

BAD Campaigns, the consulting firm Berman operates with partner Carl D'Agostino, lost only one race last year.

Because the Los Angeles area is so large and television advertising is too expensive for congressional or legislature campaigns, Berman, with his talent for demographics and computers, developed remarkably effective mailings targeted at groups most in tune with the Waxman-Berman group's issues--teachers and support for education, elderly and national health care, Jews and support for Israel.

Levine also has the ability to raise money in the rich and liberal entertainment and business communities, partly because Levine and his wife, also an attorney, are from very wealthy families with a strong commitment to Israel.

In the spirit of the Waxman-Berman system, Levine contributed $15,000 of his own campaign funds last year to Santa Barbara liberal Democrat Gary Hart, who won a state senate seat and promptly led a fight to increase the budget for the beleaguered public schools.