All of these concerns may have been sharpened and accelerated by the searing images produced by the 1992 Los Angeles riots--which claimed many immigrants as victims, but also saw many involved as participants, especially in looting. On the state and national level, that may have been an unrecognized turning point in the evolution of this issue, said Michael Fix, director of immigrant studies at the Urban Institute. "It changed the imagery of the immigrant from the exploited to a problem," he said.

A Constant Complaint

The uneasiness about immigration in California today is unique in its intensity, not its content. Skepticism among the native-born about immigrants has been as constant a factor in American life as immigration itself.

In polls conducted since 1946, only once has as much as 10% of the public said levels of legal immigration should be increased, according to Simon and Susan H. Alexander, authors of "The Ambivalent Welcome," a recent history of U.S. attitudes toward immigration. In a Gallup poll taken last summer, two-thirds of Americans said overall immigration should be reduced--double the percentage in 1965.

Other patterns persist. Consistently through American history, the public has favorably viewed earlier generations of immigrants and looked unfavorably on contemporary immigrants--often translating their sentiments into discriminatory barriers. Before the Civil War, Eastern cities experienced violent reactions against the Irish; by 1896, the secretary of the Immigration Restriction League complained that the new Italian immigrants lived in a manner that would be unacceptable to any Irishman. National polling today finds the same pattern, with positive assessments of Irish, Poles and Chinese and negative reactions toward Mexicans, Iranians and Haitians.

In the long history of American ambivalence about immigration, the depth of these anxieties about newcomers has often been a barometer of the nation's fundamental sense of confidence.

In his classic study of American nativism, "Strangers in the Land," historian John Higham describes anti-immigrant sentiment as "the defensive nationalism of an age undergoing disillusion." The decision to largely close the borders in the 1920s, he wrote, reflected not only economic and cultural concerns but also the national disillusion that followed the failure of World War I to eliminate international tensions.