Anyone who has followed America's culture wars of the past few decades can be excused for thinking that the process of assimilation is a thing of the past. Right-wing nativists have been chanting their mantra that contemporary immigrants are actively resisting mainstream culture and will never integrate. Left-wing multiculturalists and ethnic nationalists have been insisting that today's immigrants should not be expected to adopt the practices of their host country at the expense of their native culture.

But the people who come to the United States to build new lives do not live according to the prescriptions of activists or political pundits. In fact, today's immigrants are embracing U.S. life much the way previous newcomers have always done. Nowhere is the issue of immigrant assimilation more important than it is in California.

California, home to nearly one-third of the nation's immigrants, has long since replaced the Eastern Seaboard as the leading region of entry for contemporary newcomers. Los Angeles is as heavily immigrant today as was New York City in 1910.

Southern California is the destination of choice for fully a quarter of the country's foreign-born population. As such, the fate of Southern California's immigrant population is inextricably linked to the fate of the region at large.

Throughout U.S. history, each new wave of immigration has inspired debate. Although earlier immigrants were ultimately absorbed into the mainstream, each new generation of nativists found some characteristic or other that they claimed would prevent the contemporary newcomers from ever fully fitting in.

In the 18th century, Benjamin Franklin had misgivings about German clannishness and unwillingness to mix with outsiders. A century later, some worried that Irish Catholics would not only resist becoming part of a predominantly Protestant society, but also would serve as agents for the papacy.

In the late 19th and early 20th centuries, the presumed "racial" foreignness of eastern and southern European immigrants, as well as newcomers from East Asia, heightened concerns about their prospects for integrating into American life. Following that era's rage for "scientific" cultural stereotyping, many of these immigrants, including Jews, were seen as intellectually and morally incapable of ever properly assimilating. With their severe disadvantages of limited education and high levels of poverty, they seemed destined to become permanent denizens of ethnically segregated communities.

Contemporary arguments about today's immigrants tend to be a motley blend of these assertions and misconceptions. The ugliest brand comes from racialists who argue that nonwhite immigrants can never assimilate into what is at core a "white country." The more common complaint, though, focuses on the tendency of many immigrants to congregate with each other after arriving in the United States.

Latin American immigrants, who have forged sizable enclaves in several U.S. cities, are of particular concern to modern-day nativists. Their continued use of Spanish and the rising popularity of Spanish-language media have evoked pessimistic assessments of the future of American linguistic unity. Indeed, for many native-born Americans, a drive through some neighborhoods in Los Angeles or Miami seems "exotic," with restaurants that serve unfamiliar foods, stores emblazoned with strange words and clubs that play foreign music.

To many onlookers, these sights, sounds and smells are evidence of active resistance to American culture and society; to some alarmists, such street scenes even contain the seeds of ethnic secessionist movements. But there's nothing new about this pattern of gathering together.

Throughout American history, newly arrived immigrants have clustered in specific cities and states. During the first two decades of this century, immigrants composed absolute majorities of the country's urban population. Italian and Irish immigrants clustered in the northeastern corridor. Norwegians, Finns, Danes and Germans created their own enclaves in the Midwest. Polish immigrants transformed Chicago into the second-largest Polish city in the world. Japanese gathered in Los Angeles and Honolulu, while Jewish immigrants were once overwhelmingly located in New York.

The newcomers who settled together rarely discarded the language, symbols and tastes of their countries of birth upon arriving in the United States. Now, as then, these communities help immigrants adapt by mitigating the cultural shock of migration and providing crucial networks of jobs and information. Rather than being a harbinger of permanent self-segregation, these enclaves represent way stations where newcomers can gain a foothold in their new country.

As in earlier centuries, the volume of contemporary immigration has given rise to sizable ethnic enclaves in several American -- particularly Californian -- cities. The process that turns Boston green is also coloring the cultural identity of many cities up and down the coast. Los Angeles is destined to become -- culturally and politically, as well as demographically -- - a largely Mexican-American city. San Francisco is taking on an ever more obvious Asian, predominately Chinese-American, character. Vietnamese immigrants have left their imprint on Westminster in Orange County. Newcomers from Korea, the Philippines, Cuba, the former Soviet Union, and El Salvador have carved out ethnic havens in several cities and suburbs throughout the state.

For too long now, assimilation has been mischaracterized as a process of subtraction: An immigrant would be considered "Americanized" only when he had stripped himself of the past. But culture or knowledge is not a zero-sum quantity that requires an individual to forget something old in order to learn something new. Immigrants often retain some characteristics and loyalties from the old country -- whether in the form of worship, food, or holidays -- for generations to come.

Indeed, even as they enter the mainstream, larger immigrant groups have always put their imprints on American culture. U.S. culture is constantly changing and adapting to immigrants just as immigrants adapt to it. Customs or foods that were once foreign became part and parcel of local tradition -- bagels and Yiddish phrases in New York, bratwurst and beer in Milwaukee, and everything green in Boston. Immigration patterns are also what make the typical Minnesotan (of Swedish origin) look and speak differently from the typical Pennsylvanian (whose roots are German).

In places like California, Texas and Florida, today's immigrants are weaving many of their customs and traits into the mainstream. One of the main reasons so many commentators misread today's immigration patterns is that assimilation is a long-term process, sometimes taking several generations, and it does not readily lend itself to journalistic snapshots. A Salvadoran immigrant's taste for Spanish-language radio is not a reliable indicator of the linguistic preferences of his children or grandchildren.

Indeed, it is not even an indicator of his own desire to learn English. An immigrant may continue to speak with friends or family or watch television in his native tongue, but this does not prevent him from simultaneously acquiring English in order to communicate with people outside his immediate community. Indeed, census data continue to prove unequivocally what common sense dictates: that the longer immigrants remain in the United States, the more likely they are to acquire English.

In 1990, almost half of immigrants from non-English-speaking countries reported that they did not speak English proficiently within two years of arriving in the United States. Yet among those immigrants from non-English- speaking countries who had been in the country for 30 years or more, 88 percent said they spoke English well. The idea that non-English-speaking clusters remain over generations is simply untrue. In 1990, more than 90 percent of second-generation Asian and Latino children reported speaking English proficiently or exclusively.

Indeed, by the third generation, 85 percent of Asian children spoke only English. While there is evidence that Spanish remains a resilient second language among many Latinos in heavily Hispanic regions of the country, this clearly does not delay their thorough acquisition of the nation's primary language. In most families, after three generations in the United States, Spanish begins to disappear altogether. In 1990, fully two-thirds of third- generation U.S. Latino children spoke no Spanish at all.

If immigration is the story of uprooting oneself, then assimilation is the story of putting down roots in one's country of choice, and there is probably no more durable indicator of attachment to American life than homeownership. For most Americans -- native or foreign-born -- buying a home is a principal means of accumulating wealth.

A powerful symbol of stability and faith in the future, owning a home signifies that an immigrant family has attached its well-being to the fate of the country. And immigrants are home buyers. Those who have lived in the United States for at least 25 years actually buy their own homes at a higher rate than the native-born population. Despite their typically low socioeconomic status upon entering the United States, 60 percent of Mexican immigrants who came here in the late 1960s owned their own homes by the 1990s.

Last year in California, six of the 10 most common names of home buyers were Spanish surnames. Over the past few years, the political climate that inspired the greatest rush to citizenship in U.S. history also has ratcheted up Mexican immigrants' traditionally low naturalization rate. The anti- immigrant campaigns in California and in Congress pushed immigrants off the proverbial fence and inspired them to renounce loyalty to their country of origin and pledge allegiance to the United States.

In 1996, Mexico was the leading country of origin among naturalizing citizens, accounting for a quarter of total new citizens. And while naturalization rates continue to vary from group to group, the majority of immigrants do become U.S. citizens within 25 years of their residence in the United States.

For all the symbolic value that citizenship carries, there is no more profound indicator of social integration than intermarriage. It is not only a sign that a person has transcended the ethnic self-segregation of the first years of immigration, it illustrates the extent to which ethnicity no longer serves to separate one American from another. After a generation or two of living in the United States, both Asians and Latinos, the two ethnic groups that make up the lion's share of contemporary immigrants, choose spouses of other ethnicities at extraordinarily high rates. As the census data show, fully one-third of third-generation Hispanic women marry non-Hispanics, and the rate is even higher (42 percent) for Asian American women.

The vast majority of contemporary writing on immigration has focused on how newcomers affect the United States, particularly in economic terms. But immigrants do not live as financial aggregates in economic models and do not arrive in the United States as self-conscious standard-bearers of their race or ethnicity. Rather, they are a collection of uprooted individuals trying to adjust to what are often radically different conditions in their new country. They are drawn by the promise of the economically most dominant nation in history, whose culture and influence permeate the globe. It is absurd to think that immigrant families living within this country's borders somehow remain immune to its assimilative power.