Los Angeles — When California conservatives want to do an end run around the state Legislature and take issues straight to the voters, Paul Gann is their man. Mr. Gann is the crusty populist and lobbyist-at-large who teamed with Howard Jarvis to sponsor Proposition 13 in 1978, launching a national wave of tax-cutting; and Proposition 8 in 1982, the country's most sweeping get-tough-on-criminals measure. He succeeded again last week by carrying his cause past California politicians and directly to the voting public.
Although Proposition 24 was the most controversial measure on the June 5 primary ballot, only a minority of Californians had heard of it two weeks before. Yet it passed, and if the state Supreme Court upholds its constitutionality, it will significantly alter the way the Legislature does business.
The ''Gann initiative,'' as it is called, aims to change the rules and redistribute power in the California Legislature. It hits hardest at the power of the Speaker of the Assembly, presently the second most-powerful political post in the state next to the governor.
It also cuts the Legislature's budget for staff and expenses for the 1984-85 fiscal year to 70 percent of this year's spending, to increase no faster than the growth in the state's general fund.
For this measure, the real battle may be a legal one. Democrats at the Capitol promptly filed suit last week, charging that the measure illegally interfered with the Legislature's right, outlined in the California constitution , to make its own rules.
Most constitutional law experts are skeptical that the measure will be left standing. And the Democrats who control the Legislature have made it clear they have no intention of operating under the new system until they get word from the courts.
Unlike previous Gann efforts, Proposition 24 failed to arouse much public interest. It was a campaign fought bitterly, but well to the side of main currents of the news.
As the primary approached, the outcry from Democrats was high-pitched. Flamboyant Assembly Speaker Willie Brown stated in late May that under the Gann initiative, ''Government, as we know it, would cease to exist and in its place, a tyrannical minority could determine committee assignments, staff hiring and firing, and who can buy how many pencils. Are these the lessons we want to teach our children?''
For Republicans, who are a 2-to-3 minority in the Assembly, the rallying cry for Gann was for fair rules and a more dollar-efficient legislature. Assembly GOP leader Robert Naylor says the measure passed out of ''public frustration with the inefficiency and lack of representation in the Legislature.''
Under the Gann measure, the Assembly speaker loses the power to assign committee members and appoint chairmen and vice-chairmen. Instead, committee memberships are split between Republicans and Democrats by their proportion in each house, and the rules committees pick chairmen and vice-chairmen. Further cutting the clout of the majority Democrats, the measure requires a two-thirds majority to change rules or establish a committee.
To the voting public, this kind of political arcana probably captures few imaginations. It was more likely the chance to cut a politician's budget that won over the public. ''People weren't interested,'' says pollster and opinion analyst Mervin D. Field. Voters were confronting the initiative for the first time in the voting booth, or had encountered it only superficially, Mr. Field says, and saw it as a money-saving measure without understanding all the political intricacies.
''The fact that it passed only 53 to 47 (percent) is remarkable. My preelection feeling was that it would pass by much wider margins.''
''I think the (voters) knew the essence of it,'' says Assemblyman Naylor - that it would cut spending and diminish the Assembly speaker's power.
Willie Brown doesn't take the passage of the measure personally, however. Rather he chalks it up to the general readiness of voters to cut spending by politicians. They would have done the same to the Republican governor's budget if given the chance, he adds.
The legal trouble Proposition 24 may run into is that California's Constitution provides that the Legislature determines its own rules. A similar initiative in Massachusetts was struck down for similar reasons. The voting public is in fact acting as the Legislature, in legal terms, in making initiative statutes. But rules and statutes are not the same, and in imposing rules on the lawmakers by statute, ''it is binding the Legislature in a way that it cannot bind itself,'' says law professor Robert Post of the University of California at Berkeley.
One possible outcome of a decision by the state's high court, however, is that the rules portion of the measure may be struck down, leaving the spending cuts intact. If so, Republican legislators may bear the burden of the staff cut.
Mr. Naylor doesn't think Speaker Brown would play politics quite so fiercely, he says, ''But I've been wrong before.''