By Cokie Roberts and Steven V. Roberts

Here’s who President Trump’s anti-immigrant policies would hurt the most: his own base. That is, the aging white males without college degrees who form the core of his support system.

Without a vast infusion of youthful, hardworking, tax-paying immigrants, this country will find it much harder to afford the generous benefits promised to these Trump supporters as they age and retire.

“Trump’s immigration plan may seem to be a politically expedient way to reach older whites, who are fearful of the nation’s changing demography,” demographer William Frey told Ron Brownstein of The Atlantic. But “as more white baby boomers retire, the nation’s labor force and economic vitality will increasingly depend on nonwhite immigrants and their children. They will become prime contributors to Social Security and Medicare.”

Fred Hiatt argues in The Washington Post that “naked self-interest” should prompt Trump supporters to back an increase in immigration, not a rollback. “A vote to choke off immigration is a vote for stagnation and decline,” he writes.

Trump has spent his entire career stirring up resentment against foreigners, particularly nonwhite, non-Christian “others.” Barack Obama was a closet Muslim from Kenya. Mexicans were rapists. Syrians were terrorists. Africa sent the “worst of the worst” to the U.S. Haitians and Salvadorans were from “s—hole” countries. Only white Norwegians seemed to be acceptable — a clear sign of his racist impulses and undertones.

The president continued the same deeply cynical, closed-minded theme in his State of the Union speech, demonizing immigrants as gang members and terrorists, without a single word about the enormous benefits they bring to this country every single day.

Trump says he wants to protect the “Dreamers,” the approximately 800,000 young people brought here as children who know no other homeland. But the deal he offers also includes legislation proposed by two Republican senators that would slash legal immigration, which approached 1.2 million newcomers in 2016, in half.

Their proposal has two main points endorsed by the president: End a lottery that promotes diversity, and make it far more difficult for legal residents to bring in family members. The sponsors argue they want to admit more “skilled” immigrants, but that’s a smokescreen. “The purpose of this from the beginning has been to cut legal immigration,” Stuart Anderson of the National Foundation for American Policy told The Atlantic.

That’s morally despicable and un-American, to be sure. But reducing legal immigration is seriously misguided from an economic perspective, as well. Trump told Congress he wants to “put America first,” but his immigration policy would do exactly the opposite. Sen. Tom Cotton, lead sponsor of the bill Trump endorses, asserts that these newcomers have caused “a sharp decline in wages for working Americans.” But that is flat-out wrong.

The nonpartisan National Academies of Sciences, Engineering and Medicine did an exhaustive survey of the research on just this issue and concluded that the impact of immigration on wages is “very small” and dissipates quickly.

“Immigration has an overall positive impact on long-run economic growth in the U.S.,” the 2016 report stated.

Evidence from around the country overwhelmingly supports this conclusion. Older cities are competing desperately for immigrants as job-creating engines. And two Michigan institutes (Global Detroit and the Michigan Economic Center) recently reported, “Immigrants have been the main source of population gains and economic revival for once-thriving industrial communities experiencing many years of decline.”

Immigration’s impact has been huge in Silicon Valley as well as the Rust Belt. A group of high-tech companies led by Apple and Google wrote, in a court brief opposing Trump’s immigration policies, “Immigrants make many of the nation’s greatest discoveries, and create some of the country’s most innovative and iconic companies. The energy they bring … is a key reason the American economy has been the greatest engine of prosperity and innovation in history.”

The final point against Trump and in favor of greater immigration is simple demographics. “A drastic, absolute drop in the level of immigration,” writes Hiatt, “would be turning us into Japan,” an “aging, shrinking nation” that cannot sustain economic growth or support its burgeoning elderly population.

Social Security estimates that the number of seniors will grow from 48 million now to 86 million in 2050. But if immigration is cut in half, projects the Pew Research Center, the workforce will not grow at all.

“That’s a recipe either for unsustainable tax increases or big benefit cuts in the Social Security and Medicare programs indispensable to Trump’s base,” writes Brownstein.

In short, when Trumpians cheer the president’s call for reduced immigration, they are endangering their own future. As Trump might tweet: SAD.

Steve and Cokie Roberts can be contacted at stevecokie@gmail.com.