Gil Olivarria, a strapping police lieutenant, is running what appears to be a razor-close race for the California Assembly in this desert district stretching more than 150 miles east of Los Angeles to the Colorado River.
If he wins, he will be the first Mexican-American wearing the Republican label in the California legislature since 1907 - in a state 16 percent Hispanic.
Mr. Olivarria's race - obscure though it is - carries the banner for the just-stirring effort to build a Republican political base in the fast-growing Mexican-American communities of the Southwest.
Hispanics and Republicans are relatively new to each other. California Republican leaders, including Gov. George Deukmejian, are vigorously backing Olivarria with money and campaign appearances. Democrats, including the state's most influential Mexican-American politicians from East Los Angeles, are pulling out all the stops to beat him.
Like other Latino Republicans, Olivarria has to battle on two fronts. First, he must win acceptance from Mexican-Americans, who frequently perceive the GOP as the party of the rich. Second, he must win acceptance by Republicans, overcoming any lingering racism and the perception that Latinos are liberal.
Mexican-Americans, who make up a more than 60 percent and growing share of the US Hispanic population, have been solidly Democratic for decades. But there has been an increasing willingness among Mexican-Americans to vote for Republican candidates in recent years, and Latino activists have become increasingly disillusioned with the Democratic Party.
Olivarria himself was a Democrat by inheritance until he registered as a Republican in 1979. He liked the traditional, law-and-order conservatism of George Deukmejian, he says, and opposed the New-Age liberalism of then-Gov. Jerry Brown.
Republican politicos know that if they want to make inroads into the Hispanic electorate, they must cultivate Hispanic Republican candidates like Olivarria, as well as develop a base of financial supporters among Mexican-American businessmen and professionals.
Julio Calderon, who is starting a political-action committee for Hispanics and is former president of the Mexican-American Political Association, spotted Olivarria in 1982 when the officer often was in the news as spokesman for the Riverside police. Mr. Calderon called him and began encouraging him to run for office.
Calderon was a Democratic Party regular until that year. In the 1960s he had been a Chicano activist in La Rasa Unida (''united race'') Party. But when he saw the Democratic leadership in California working to defeat Latino candidates in Democratic primaries, he grew skeptical that the Democrats had Latino interests at heart.
And, like many Latinos, Calderon had come to feel that the Democrats had grown out of tune with the basically conservative Latino community. So Calderon switched parties and began looking for Latinos with potential as GOP candidates.
His goal, he says, is to bring the two-party system to the currently Democratic Hispanic community. A healthy competition would force both parties to pay more attention to Hispanic concerns. ''The stronger the Hispanic GOP becomes , the more important Hispanic Democrats will be to the Democrats,'' he explains.
''We still have a common goal in mind. We want to see our people advance politically and professionally,'' says Calderon. ''But we're not asking for anything to be given to us. We're breaking away from the welfare mentality of the liberal Democrats.''
Ten years ago, Richard Hernandez, a Los Angeles lawyer and founding president of the Hispanic Republican Council, was finance chairman for East Los Angeles Assemblyman Richard Alatorre, who now may be the most influential Latino in state politics. Mr. Alatorre is a Democrat.
''The priority,'' Mr. Hernandez says, ''was to get Hispanics into the political system.'' Now, he is across the party fence from Alatorre, who has been to Riverside to campaign against Olivarria.
As long as Republicans write them off and Democrats take them for granted, says Hernandez, ''Hispanics, politically, have the worst of both worlds.''
Gloria Molina, like Alatorre, is a Democratic member of the Assembly from East L.A. She also has campaigned against Olivarria. But she acknowledges that the Democratic leadership has not been responsive to Hispanic concerns.
She has worked at both the state and national Democratic conventions, she says, to get the ear of the party on issues of special concern to Hispanics - such as tax credits to defray the cost of sending children to parochial schools. ''I've been totally ignored,'' she says. ''Really totally ignored.'' She adds: ''We're going to continue to lose those voters until the party wakes up to it.''
But her answer is not to turn to the Republican Party, which she believes is not concerned with the interests of the poor and minorities. Rather, she says, it is for Hispanics to vote aggressively according on the issues important to them.
In Orange County, Rudy Montejano agrees that Hispanic voters need to be issue-oriented, rather than partisan. ''We all have to hang together for Hispanic concerns, regardless of party affiliation.''
But Mr. Montejano, a Santa Ana lawyer and county Hispanic chairman for the Reagan-Bush Committee, joined the GOP in 1982. This fall he finished putting every Hispanic voter in his north Orange County congressional district onto a computer list. Each household will soon receive a mailer from the Reagan campaign.
With a list like this, Montejano can cultivate grass-roots Republicanism - a Santa Ana councilman, an Orange mayor.
''For the first time,'' says Sergio Arredondo, the state Hispanic chairman for Reagan-Bush, ''there is a Hispanic structure'' to welcome Latino newcomers into the Republican Party.