Support for, or opposition to, mass immigration is apparently a class issue, not an ethnic or racial issue. Elites more often support lenient immigration policies; the general public typically opposes them.

Support for, or opposition to, mass immigration is apparently a class issue, not an ethnic or racial issue. Elites more often support lenient immigration policies; the general public typically opposes them.

At the top of the list are Mexico's elites. Illegal immigration results in an estimated $25 billion sent back in remittances to Mexico each year. The Mexican government worries more about remittances, the country's No. 1 source of foreign exchange, than it does about its low-paid citizens who are in the U.S., scrimping to send money back home. Remittances also excuse the Mexican government from restructuring the economy or budgeting for anti-poverty programs.

Mexico sees the United States the way 19th-century elites in this country saw the American frontier: as a valuable escape hatch for the discontented and unhappy, who could flee rather than stay home and demand long-needed changes.

American employers in a number of industries � construction, manufacturing, hospitality and others � have long favored illegal immigration. Low-wage labor cuts costs: The larger the pool of undocumented immigrants, the less pressure to raise wages. That was why Cesar Chavez's United Farm Workers in the 1970s occasionally patrolled the southern border in its vigilante-style "illegals campaign" to keep out undocumented immigrants while opposing guest-worker programs.

Moreover, the additional social expense associated with millions of undocumented workers � in rising health care, legal, education and law-enforcement costs � is usually picked up by the public taxpayer, not by employers.

Ethnic elites also favor lax immigration policies. For all the caricatures of the old melting pot, millions of legal immigrants still rapidly assimilate, integrate and intermarry. Often within two generations of arrival, they blend indistinguishably into the general population and drop their hyphenated and accented nomenclature. But when immigration is mostly illegal, in great numbers and without ethnic diversity, assimilation stalls. Instead, a near-permanent pool of undocumented migrants offers a political opportunity for activists to provide them with collective representation.

If the borders were closed to illegal immigration, then being Hispanic would soon be analogous to being Italian-, Greek- or Portuguese-American in terms of having little prognostic value in predicting one's political outlook. The continual flow of indigent new arrivals distorts statistics on poverty and parity, prompting ethnic elites in politics, journalism and higher education to seek redress for perennial income and cultural imbalances. Offering affirmative action to a third-generation Hispanic-American who does not speak Spanish apparently is seen as one way to help thousands of recently arrived impoverished immigrants from Oaxaca, Mexico, find parity.

High-income American elites likewise have largely favored illegal immigration for a variety of predicable reasons. The professional class likes having low-wage "help" to clean the house, cook meals, help take care of kids and elders, and tend the lawn.

Elites have ways of navigating around the downsides of illegal immigration. They can avoid crowded schools and low-income neighborhoods, and they can easily pay the higher taxes that can result from illegal immigration.

Support for lax immigration policies also offers psychological penance for essentially living a life of apartheid. An elite can avoid living in integrated neighborhoods or sending his children to diverse schools, but he can square that circle by voicing theoretical support for immigrant amnesty and sanctuary cities.

Who does not benefit from mass illegal immigration? Mostly the poor, minorities and the lower-middle class. They are not employers, but rather compete with undocumented immigrants for low-wage jobs. They cannot afford to send their children to a different school when theirs becomes overcrowded. They cannot afford the increased taxes needed for social support of millions of new arrivals.

Donald Trump tried to demagogue illegal immigration along ethnic lines. But the issue is not where illegal immigrants come from or who they are, but rather their effect on the struggling working classes already here.

Prune away the rhetoric and the issue becomes simple: Elites profit from high-volume illegal immigration, while most other U.S. citizens only support immigration when it is legal, measured and diverse.

Victor Davis Hanson is a classicist and historian at Stanford University's Hoover Institution.