Los Angeles — The cliche is still that to be born Mexican-American is to be born Roman Catholic and Democratic. It's true, says Rudy Montejano, but ''it's changing.''
An Orange County lawyer and a Mexican-American, Mr. Montejano has been a Democratic leader among local Latinos for years. He has campaigned for Jerry Brown, Hubert Humphrey, George McGovern, and Jimmy Carter.
This year it's Ronald Reagan. Mr. Montejano became a Republican two years ago. He is now Hispanic county chairman for the Reagan-Bush campaign. His wife is still a Democrat, but his son is active in the Republican Party as a high school sophomore.
''The Democratic Party left me,'' Rudy Montejano says. ''Many Hispanics really think along the lines of Republican principles, even though they're still Democrats.'' More than anything, he explains, Hispanics want to ''get away from the poverty, welfare, handout mentality.''
Although there is no evidence that significant numbers of Hispanics are switching their party registration - like Montejano - to the Grand Old Party, there are signs that Republicans are getting more Hispanic votes and more Hispanic sympathies than in the past.
Montejano is unusual, but not too unusual. For the past two years, the GOP has been aggressively courting Hispanics across the country, trying to establish a solid foothold in a community that was once monolithically Democratic.
Hispanics are growing fast in voting strength, especially in the Southwest. The final numbers have not been tallied yet, but according to Southwest Voters Registration and Education Project, close to a million new Hispanic voters have been added to registration rolls since 1980, nearly a 30 percent increase. The 1980 number was a 30 percent increase over the number of registered Hispanics in 1976.
This is a constituency the Democrats have been able to count on since the 1930s (except for the staunchly Republican Cuban-Americans), while Republicans have typically written them off - as they have blacks - as being solidly Democratic.
But American Latinos are in many ways conservative, and election results show that the Democratic Party's hold on them has been slipping for the past 15 years. Now, as Hispanics emerge as a major constituency in the big electoral states of Texas and California, the slippage appears to be accelerating.
In 1980, Ronald Reagan got a larger share of the Latino vote - 25 percent - than any Republican presidential candidate in two decades. In 1982, a bad political year for Republicans, California Gov. George Deukmejian took 27 percent of the state's Latino vote.
The current picture is difficult to sort out, but it appears to show unprecedented Republican strength.
Reagan-Bush tracking polls show their ticket carrying 40 percent of the Hispanic vote nationwide. Mondale-Ferraro polls in California show Reagan with a similar percentage. A California Poll taken over September and October showed Reagan actually leading Mondale among Hispanics 44 percent to 43.
On the other hand, a Los Angeles Times poll this month showed Reagan favored by only 31 percent of California Latinos, to Mondale's 65 percent. But even at 31 percent, Reagan is running well ahead of the 22 percent of California Latinos he won in 1980.
''If Ronald Reagan does 40 percent (among Hispanics) like the polls say he's going to do, and (if) that's not an awakening to the Democrats that the party of FDR and JFK is losing its hold, then I don't know what will be,'' says Fernando Chavez, president of the Mexican-American Political Association (MAPA) and son of farm labor leader Cesar Chavez.
Few GOP activists hope to convert a majority of American Hispanics to Republicanism. Their goal over the next few years is simply to make the GOP competitive enough to call the Hispanic electorate a two-party constituency.
They have several factors in their favor. In general, American Hispanics are culturally conservative, traditional, family oriented, and intensely patriotic - not, rightly or wrongly, characteristics widely associated with the current Democratic Party leadership. Many Hispanics favor tax credits for the cost of sending their children to parochial schools, favor prayer in public schools, oppose abortion as Catholics, and favor the Simpson-Mazzoli immigration bill - all of which put them at odds, to some degree, with Democratic positions.
The economy cuts both ways. The current recovery favors the Republicans, but much of it has not reached the Hispanic community. Hispanic unemployment is still at the 1980 level of 10.7 percent, according to the Center on Budget and Policy Priorities in Washington, and the typical Hispanic family lost $600 in real-dollar income from 1980 to '83.
The greatest obstacle Republicans encounter in the Hispanic community is the entrenched perception that the GOP is the party of the rich. A clear majority of Hispanics are still in the poor and working classes. Republicans offer themselves instead as the ''party of opportunity,'' meaning, basically, the party of jobs.
There is a perception that the Democrats are growing further out of sync with Hispanics. Hispanic leaders, who are overwhelmingly Democrats, ''have been left behind by the community,'' says Julio Calderon.
Mr. Calderon, like Rudy Montejano, was a Democratic activist until 1982, when he became Republican. Past president of MAPA, he is in Sacramento now starting a political-action committee for Hispanic politicians.
''Our leaders are stuck in the rhetoric of the '60s,'' he says. ''There is a pride in the Hispanic community that has never bought into the welfare mind-set.''
As the Democrats seemed to stall out, the Republicans have gone on the offensive for Latino voters.
Two years ago, Tirso del Junco, a Cuban-American doctor and prominent leader among California Republicans, was greeted with skepticism when he told Reagan campaign officials that the President could carry 35 percent of the Hispanic vote. Now that is considered low.
''My biggest problem,'' he says, ''has been to convince my Republican brothers that this is worthwhile.''
Reagan speeches are translated into Spanish and sent out to 150 Spanish-language radio stations. There are Reagan-Bush field offices for Hispanics in nine California counties now, some more active than others, but all getting party support.
In Texas, Republicans are using the election to build a network of Hispanic GOP regulars in the 26 counties with 10,000 or more Hispanic voters.
Politicos in both parties agree that Republicans are working harder and spending more money to court Hispanics than are Democrats. But then, Republicans have a lot of ground to make up.
It was Franklin D. Roosevelt's New Deal programs that first made Democrats of the Mexican-Americans of the Southwest in the 1930s. Mr. Roosevelt was revered ''almost like a saint in some communities,'' says Mario Garcia, a historian at the University of California at Santa Barbara. Roosevelt's status was later rivaled by that of John F. Kennedy, who was not only Roosevelt-like in his charisma, but Roman Catholic.
Mexican-Americans were at least 90 percent Democratic through the Johnson administration. After that, the party's hold began to slip - especially among middle-class Latinos, Professor Garcia notes. For these people, he explains, Republicanism is perceived as ''part of their new status and upward mobility. The Democratic Party is seen as reverting to the old barrio.''
''This is a new thing,'' says Sergio Arredondo, a Los Angeles contractor and Hispanic state chairman for the Reagan-Bush ticket - new for Republicans, who are used to writing off Hispanic communities to the Democrats, and new to Hispanics, most of whom were born into a Democratic tradition.
''For the first time there is a Hispanic structure'' in the GOP, he says. ''We're looking beyond our nose now.''
Next: Republican efforts to build a party structure in the Hispanic community