Late last year, California's Democratic House delegation drew up a list of legislative priorities for the 100th Congress. A key item was a dramatic increase in the federal commitment to battling AIDS, which has plagued California more than any other state except New York.

The campaign began in earnest in February, when -- at the urging of Rep. Barbara Boxer of San Francisco -- the House Budget Committee devoted one of its four field hearings to AIDS. The following month, when committee Democrats met privately to write a budget resolution, Boxer and her two California colleagues on the panel made it clear they would oppose any budget that did not include a major boost in AIDS funding.

By mid-April, the full House had adopted a fiscal 1988 budget that would double the amount to be spent on AIDS research and education while cutting the growth of overall domestic spending by $9 billion. The $970 million allocated for AIDS was 82 percent higher than the amount sought by the Reagan administration and represented the largest increase in the $1 trillion federal budget.

The successful drive to increase AIDS funding clearly owed something to Congress' heightened awareness of a national health emergency. But it also illustrates the growing clout of the California delegation, which is increasingly viewed as the most influential in the House.

California's evolution into a House power is also an object lesson in how things get done in Washington. Bright, shrewd, hard-working and cohesive, California Democrats are gaining the seniority to climb the leadership ladder and possess the political agility to skip some rungs.

"As it has become more Democratic on the congressional level, California has become more and more effective," said Christopher Matthews, who was an aide to former House speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.). "They don't stay in the pocket; they're always out there scrambling."

Through sheer size, California's House contingent would play a major role. At 45 members -- more than 10 percent of the House -- it is the largest state delegation and will grow again after 1990 census. Twenty-seven of the Californians are Democrats.

But California's legislative prowess is not just a function of its bulk. Despite some handicaps -- Democrats and Republicans rarely pull in harness and lawmakers from other states occasionally rebel against its influence -- the California delegation has the potential to dominate the House as Texas did during the two decades after World War II.

The key to legislative dominance is longevity, and California's Democrats have achieved extraordinary job security at the time when retirements have thinned the ranks of senior House members.

Thanks to a clever redistricting map fashioned by their late chairman, Rep. Philip Burton, Democrats picked up six additional congressional seats following the 1980 census, and now outnumber Republicans 27 to 18. (The year before redistricting the Democrats only had a 22 to 21 edge over the Republicans.) But more importantly, the seats are safe. In 1984, the year of Reagan's reelection landslide, only one Democrat lost. Last year, only six Democrats received less than 65 percent of the vote, and the closest of their races was a 57-to-43 runaway.

As a result, a bevy of relatively young California Democrats, many first elected to the House in the 1970s after earning their spurs in local and state government, has moved into positions of authority and is poised to advance further.

In the 100th Congress, House Democrats from California hold 27 committee and subcommittee chairmanships, as well as the No. 3 spot in the Democratic leadership. Name almost any policy area in Congress and at least one Californian is positioned to affect the outcome.

Among the prominent figures are:Rep. Tony Coelho, the House Democratic whip. His six years as head of the Democratic Congressional Campaign Committee made him a power in national politics and built him a loyal following among House colleagues who benefited from his fund-raising. Rep. Leon E. Panetta, an expert on budget issues who is a contender to take over the Budget Committee's chairmanship in 1989. He chairs an Agriculture subcommittee. Rep. Henry A. Waxman, a tenacious political infighter whose chairmanship of a subcommittee on Energy and Commerce has made him a leader on health-care issues. With Rep. Fortney H. (Pete) Stark heading the health subcommittee of Ways and Means, California holds almost a monopoly on health policy. Rep. Vic Fazio, the delegation's premier logroller. He is a key player on the Budget Committee and an authoritative voice on defense issues, but his real forte is Appropriations. On the House's most important committee for dispensing favors, he is on the water projects subcommittee and chairs the legislative subcommittee that controls the flow of institutional perquisites. As one of 13 subcommittee chairmen, Fazio is one of three Californians in the "College of Cardinals," as House conferees on Appropriations bills are known. It is this clout on Appropriations, for example, that has allowed California lawmakers to block Reagan administration plans to drill for oil off California's shores. Rep. George Miller, chairman of the Interior and Insular Affairs subcommittee on water and chairman of the Select Committee on Children, Youth and Families. Miller is likely to become chairman of Interior if Rep. Morris K. Udall (D-Ariz.) retires. Others in powerful positions include Rep. Augustus F. Hawkins, who chairs the Education and Labor Committee, Rep. Ronald V. Dellums, who chairs the District of Columbia Committee and an Armed Services subcommittee with jurisdiction over military bases, Rep. Julian C. Dixon, who chairs the ethics committee, and Reps. Glenn M. Anderson and Norman Y. Mineta, who respectively head the Public Works subcommittees on surface transportation and aviation.

California's formidable base in almost every committee in the House is no accident. Committee assignments are sought with an eye to the collective good. And to maximize the benefits of seniority, committee-hopping is discouraged.

Fazio and his colleagues, for example, are already roughing out a long-term strategy to place their newest member on Appropriations. Nancy Pelosi, elected June 2 to fill the seat of the late Sala Burton (who had succeeded her late husband, Philip), will likely start out on the Banking Committee. But Fazio believes alliances can be forged with the women's caucus and Italian American members to get Pelosi on Appropriations in 1989.

"We parlay what we have," Fazio said.

The California parlay also extends to currying favor with members from other states, principally through campaign fund-raising.

Following Waxman's lead, more than a half-dozen California Democrats have established political action committees (PAC) to funnel contributions to other congressional candidates.

When Maryland Rep. Barbara A. Mikulski was raising funds for her successful Senate race last year, for example, she turned for help to Waxman, her subcommittee chairman on Energy and Commerce. Waxman set up a Washington fund-raiser with representatives of the health-care industry, introduced Mikulski to wealthy contributors in Los Angeles' entertainment and Jewish communities, and donated $5,000 from his PAC.

With an eye to the next congressional redistricting, California Democrats also are active in state politics. A delegation PAC run by Fazio contributed about $60,000 to the state Senate campaign of Cecil Green, who recently won a special election for a southern California seat that will solidify Democratic control of that chamber.

Although California Democrats do have their areas of disagreement -- water issues, farm-worker disputes with growers -- they exhibit considerable harmony given the diversity of their large state.

"There don't seem to be people going at cross-purposes, vying for position or jockeying with each other," said Rep. Howard L. Berman of Los Angeles.

The credit goes to the delegation chairman, Rep. Don Edwards. In contrast to Philip Burton, whose domineering personality and style led to internal bickering and ego conflicts, Edwards' gentle stewardship has permitted the talents of younger members to flower.

A leading civil libertarian, Edwards has limited his ambitions to using his chairmanship of the civil rights subcommittee on Judiciary to fight the Reagan administration's social agenda.

As head of the California Democrats, he has set up a full-time office to coordinate policy and established a weekly strategy breakfast.

Edwards, said Waxman, "has done a magnificent job of bringing us together in a way that makes everyone feel like they are participating."

Yet not even Edwards' inclusive style of leadership has bridged the major chasm that separates California Democrats and Republicans. They not only rarely work together but have not held a formal joint meeting since 1981.

California Democrats are among their party's most consistent liberal voices; California Republicans are one of the most conservative GOP delegations in the House.

Rep. Duncan Hunter, a Republican from the San Diego area, noted: "California is the most politically polarized state in the nation. On major votes, you find every single Democrat voting against the president and every Republican voting for him. In Texas, it's difficult to tell the difference . . . . "

The ideological antagonisms have been exacerbated by a drawn-out political and legal battle over Burton's reapportionment plan, which state Republicans are still seeking to overturn.

"We feel the Democrats stole five seats from us in the House," said Rep. William E. Dannemeyer, an Orange County Republican. "That's a profound loss that really makes it difficult to adopt an attitude of love and affection."

Although the two groups do unite on some issues -- the wine and entertainment industries for instance -- the list is short. "I ought to be able to rattle off dozens," said one Republican as he groped for examples of bipartisanship. "If you asked a member of the New York delegation, it would not be such a strain."

Because of the circumscribed role of Republicans in a House dominated by Democrats, GOP members from California have less influence than their Democratic colleagues. But within Republican circles, their role is growing.

Rep. Robert J. Lagomarsino is secretary of the House Republican conference. And Rep. Jerry Lewis this week was elected chairman of the GOP Policy Committee, the No. 4 spot in the Republican leadership.

A number of California Republicans argue that their state delegation's partisan divisions limit its clout in the House.

"The Texas delegation gets together as Democrats and Republicans to figure out how to take California to the cleaners," said Rep. William M. Thomas.

Of more concern to Democrats is other states' festering resentment of California's growing influence. "We may have the right position on an issue, but when the label California is attached to it, it looks like a power move," Panetta said.

That was a contributing factor when Speaker Jim Wright (D-Tex.) tapped Arkansas' Beryl Anthony Jr. -- instead of Fazio -- to succeed Coelho as chairman of the Democratic Congressional Campaign Committee this year.

Despite that setback, California Democrats predict that their sphere of influence will widen in coming years.

"Because of Wright, Texas still controls the trophy," said one California lawmaker, "but it's only symbolic control."