The White House finally issued its official statement on what it wants in exchange for helping young people who were brought to the United States illegally as children — a list of demands that goes beyond a multibillion-dollar border wall. It’s a sea change in the American immigration debate.

The argument is no longer even superficially about the specter of illegal immigration and its putative challenge to the rule of law. Instead, the debate is now squarely about legal immigration — specifically, Trump’s determination to cut it roughly in half — and his vision is one of a poorer, weaker United States of America that will be more rapidly eclipsed by its rivals on the world stage and less great in almost every way.

In his preferred rhetorical constructs, Trump is putting “America First,” counterposing the interests of natives with those of newcomers. The truth is that this reflects nothing more than Trump’s own longstanding knee-jerk racism paired with Republican leaders’ increasing willingness to pander to this particular form of nativist prejudice.

America has, historically, been a place of refuge for the oppressed. But the possibility of immigration to the United States has never been an act of charity — it’s a strategy for national greatness. There’s a reason that Abraham Lincoln, America’s greatest president, serving at America’s moment of greatest national crisis, signed into law “An Act to Encourage Immigration.”

At a moment when the toxin of white supremacy threatened to literally destroy the country, Lincoln recognized “immigrants as one of the replenishing streams appointed by providence to repair the ravages of internal war and its waste of national strength and health.”

Our current national crisis is, fortunately, less profound than the one of Lincoln’s day. But Trump and the likes of Tom Cotton, Jeff Sessions, and Stephen Miller pose fundamentally the same question: Will America live up to the inherent potential of a nation conceived in liberty and dedicated to the proposition that all people are created equal, or will it sink to the depths of narrow ethnic politics in a way that is unworthy of its great purpose?

Immigration makes America more prosperous

The main sources of immigration — and the main occupations likely to employ immigrants — have changed over time, but the story has been the same from the beginning. A larger and more diverse population supports more intensive development of the resources available and a more complex division of labor, leading, over time, to a steadily more sophisticated and prosperous national economy.

Indeed, there is a fairly firm consensus that immigration raises incomes on average for native-born workers. When the University of Chicago’s Booth School surveyed a panel of well-known academic economists, for example, 52 percent agreed that admitting more low-skilled immigrants to the United States would make the average US citizen better off. Just 9 percent disagreed. The panel agreed that more highly skilled immigrants would be good by an even more overwhelming 89-0 margin.

This is not, incidentally, because an increase in the labor supply has no adverse effects for anyone. Rather, as Heidi Shierholz of the liberal Economic Policy Institute emphasizes in her overview of the literature, it’s that “earlier immigrants are the group that’s most adversely affected by immigration” because they are the people whose skill sets are most likely to put them in direct competition with new immigrants. Across a range of estimates, the effects on wages “tend to be very small, and on average, modestly positive.”

That’s because, as Michael Greenstone and Adam Looney of the center-left Hamilton Project put it, “immigrants and U.S.-born workers generally do not compete for the same jobs; instead, many immigrants complement the work of U.S. employees and increase their productivity.”

If a bunch of new monolingual Spanish-speaking construction laborers move to town, in other words, that probably is bad news for the monolingual Spanish-speaking construction laborers — mostly immigrants — who are already there. But the presence of those laborers in town will create job opportunities for people to manage them, likely native-born workers who speak English. And by increasing the number of construction projects that are undertaken, they increase the demand for more skilled tradespeople — plumbers, electricians, and others whose work is complementary to that of more generic laborers.

Trump’s priorities are completely backward

One key move Trump has made in the debate has been to downplay his proposal to cut the volume of legal immigration in half and focus instead on his criticisms of the diversity visa lottery (whose operation he systematically mis-portrays) and of family-based visas (the dreaded “chain migration”) relative to what he terms a “merit-based” system.

The diversity visa, which Trump has proposed killing in exchange for a path to citizenship for DREAMers, is, indeed, no great shakes and could fairly easily be replaced by something better. And reasonable people can disagree on the relative merits of issuing visas based on family ties to American citizens (which promotes assimilation and is a nice favor to American citizens with family ties abroad) versus based on job skills (which promotes economic growth).

Indeed, one specific element of the Trump-endorsed RAISE Act — giving preference to 20-something immigrants over younger or older ones who are otherwise similarly situated — is a straight-up good idea, since immigrants who are too old for school but much too young to retire have the most beneficial impact on the federal budget.

But to understand the proposed changes to the immigrant mix as the core of Trump’s approach is backward. After all, if you believed you had a way to substantially improve the quality of immigrants to the United States, you would want to recruit more of them, not fewer.

The right way to understand Trump’s demand is that what he really wants is a sharp cut in the total number of immigrants. The change in the skill mix is then a follow-up concession to the business community, which rightly views an immigration crackdown as bad for the economy but can have its opposition muffled by shifting to business priorities in terms of who gets a visa.

As Jane Coaston has written for Vox, Trump’s concern about the total volume of immigration to the United States seems profoundly rooted in white panic about the passing of the country’s white Christian majority. Generations ago, when immigration from Eastern and Southern Europe threatened the status of white Protestants as a majority, we had a similar nativist backlash. The good news was that America was, at that time, facing no serious challenge to its global economic preeminence. Today we don’t have such good fortune, and Trump is flying the flag of “America First” while promulgating a strategy for national decline.

Immigration enriches culture and expands options

Wages are easy to measure, so many studies focus on them for the sake of methodological simplicity. But there is more to life than cash wages, and studies show that immigration has significant indirect benefits.

One example is what Michael Clemens, Ethan Lewis, and Hannah Postel found when they looked at what happened in the 1960s when the United States decided to eliminate Mexican guest workers from America’s agricultural labor force. These guest workers, called braceros, were heavily present in some states, like Texas and California. Other states, such as Georgia and Wisconsin, had a few braceros. Some had no braceros whatsoever. By comparing wage trends in high-exposure, low-exposure, and no-exposure states, the researchers were able to show that kicking out the guest workers had no real impact on farm wages.

That doesn’t mean the laws of supply and demand were magically repealed. It means that landowners changed their strategy. For some crops, like tomatoes and sugar beets, producers were able to switch to more mechanical harvesting techniques — compromising on quality in the case of tomatoes.

For other crops — including asparagus, fresh strawberries, lettuce, celery, and cucumbers, for example — mechanization techniques were not available, and production simply fell. Wages did not rise; instead, Americans learned to live with reduced produce variety.

This same variety impact exists on the retail and service side of the economy as well. If you visit a place with few immigrants from Mexico — France or Fargo or what have you — you don’t find that taqueria workers are earning vastly more money than their counterparts in Texas. You find that there are few good places to buy tacos.

This isn’t the end of the world, any more than an asparagus shortage would be an acute social crisis, but that’s exactly why eliminating foreign-born workers doesn’t boost wages. People simply make do without the variety that immigrants provide.

Giovanni Peri and Gianmarco Ottaviano find that the value of increased cultural diversity of this sort can be partially measured through higher housing values in more diverse cities — people are willing to pay more for the amenity value of ethnic food — but will miss the extent to which a nationally rising tide lifts all boats.

Immigration strengthens the federal budget

Immigration skeptics often pivot from the basic terrain of labor market economics to the notion that immigrants — especially the dreaded undocumented — are a drain on public resources, thus keying in to longstanding racialized perceptions of the welfare state. Trump went so far as to repeatedly claim on the campaign trail that undocumented workers are actually receiving more generous public services than America’s veterans.

This idea plays a critical architectural role in holding together the political coalition of contemporary conservatism — selling the idea that cutting taxes is compatible with financial support for the elderly because there will be plenty of money for everyone once we get rid of the foreign-born leeches.

But it’s completely false. Unauthorized workers receive few if any public services (they ride the bus, but they’re ineligible for social assistance programs) but contribute to the tax base. Indeed, since people living and working in the United States illegally are often paying Social Security taxes without collecting benefits, they are in some ways the great heroes of the US Treasury.

For the immigrant population at large, the best research on the fiscal impact of immigration comes from the National Academies of Sciences, Engineering, and Medicine, which concluded that over the course of a 75-year time horizon, “the fiscal impacts of immigrants are generally positive at the federal level and generally negative at the state and local level.” Immigrants, in other words, pay more to the federal government in taxes than they receive in benefits, while the reverse is true for state and local governments.

This adverse impact on state and local governments is important, and derives largely from the fact that immigrants have kids who end up needing to go to school. The good news is that those kids grow up to be second-generation adults who “contribute the most of any generation to the bottom line of state balance sheets.”

Trump’s approach is a betrayal of America

In 1783, George Washington told newly arrived immigrants from Ireland that “America is open to receive not only the opulent and respectable stranger, but the oppressed and persecuted of all nations and religions.”

Abraham Lincoln in an 1858 speech reflected on America’s population of recently arrived immigrants from Europe, noting that “when they look back through this history to trace their connection with those days by blood, they find they have none,” but “when they look through that old Declaration of Independence,” they find a statement of moral principle, and “that they have a right to claim it as though they were blood of the blood, flesh of the flesh, of the men who wrote the Declaration, and so they are.”

Ronald Reagan elaborated on the same themes in 1988, arguing that “America represents something universal in the human spirit” and referred to a letter he recently received that read, “You can go to Japan to live, but you cannot become Japanese. You can go to France to live and not become a Frenchman. You can go to live in Germany or Turkey, and you won’t become a German or a Turk.” And yet, “Anybody from any corner of the world can come to America to live and become an American.”

These leaders across a span of two centuries shared a profound commitment to American nationalism, and thus to America’s status as a country that is not simply a place one might move to but a cause that can be joined. Over time, that cause has mostly prospered as many have joined it. And today’s Americans are privileged not to face the kind of acute military threats that dominated much of the 20th century.

But due to rapid growth in the economy of China — and that country’s staggeringly large population of more than 1.2 billion souls — the United States is also close to losing its status as the world’s No. 1 economic powerhouse in a way that hasn’t previously been on the table.

People who seriously want to put America first should want to push back against the forces driving us into second-place status, and the fact that tens of millions of people from around the world would like to move to the United States — and that we have a long and proud tradition of welcoming newcomers into our national community — should be high on the list of our potential advantages in the 21st century. For Trump and his allies to abandon that advantage for no reason respectable enough to even state clearly is nothing short of a fundamental betrayal of the nation's promise.