The U.S. is on the brink of a baby bust. The GOP will make it even worse.

After decades of growth almost quintupled the world’s population to nearly 8 billion, that trend is finally reversing. The New York Times last Saturday published a lengthy look at how stagnating birth rates are threatening to reshape countries around the globe.

It’s an interesting look at the hard choices that governments will be forced to make as death rates surpass birth rates and elderly citizens begin to outnumber their working-age counterparts. But what struck me in reading about the impending population crunch is just how shortsighted — but narrowly targeted — the anti-immigration movement in the United States truly is.

There are a lot of factors behind the dip in birth rates, including: societal norms shifting away from large families; improvements in health care and a corresponding plunge in infant mortality rates; economic insecurity among millennials who are putting off having children; and fears of climate change’s effects on a new generation. All of them put together compose the picture that the Times laid out, where countries such as South Korea and Italy are forced to plan for a world where schools shut down for lack of students and maternity wards close for lack of use.

This shift is occurring even “in countries long associated with rapid growth, such as India and Mexico, birthrates are falling toward, or are already below, the replacement rate of 2.1 children per family,” the reporters write. That in turn is accelerating a trend that’s already been the case in many developed countries. Here in the United States, the birthrate fell for the sixth year in a row in 2020; meanwhile, the last decade saw the country’s population grow by the second-lowest amount since the government first started tracking such things.

So why, with a replacement rate of around 1.6, has the United States mostly been spared the struggles that other countries are facing? In a word: immigration. The Pew Research Center estimated in 2015 that over the next 50 years, immigrants and their descendants “are projected to account for 88 percent of the U.S. population increase, or 103 million people, as the nation grows to 441 million.”

America’s economic engine has always required a steadily growing pool of labor to keep things chugging along, both in terms of producing goods and services and then acting as consumers on the demand side. Since the previous, extremely racist, quota system was replaced in 1965, a growing amount of that labor is coming from new arrivals — the percentage of the country that’s foreign born has more than doubled over the last half-century. And last year, an estimated 17 percent of the U.S.’s civilian labor force was foreign-born, according to the Bureau of Labor Statistics, a number that’s increased by a little over 4 percent since 2001.

That growth has helped prevent a situation like what China is facing, where the working-age population shrinks while the elderly population grows, leaving a smaller workforce struggling to support their forebears’ pension programs and other entitlements. Between that and the research that shows a net positive impact economically from immigration, you’d think that staving off a demographics crunch would be a pretty big priority for the supposedly pro-business Republican Party. But then you realize just who inside the party is advocating the loudest for reduced immigration these days.

It’s no secret that former President Donald Trump depended on support from white nationalists in his rise to the White House, with his polemics against immigrants and attacks on minorities more broadly. Many of Trump’s followers have expressed their belief that white Americans were losing out to these groups, and only Trump could reverse their fortunes. Their faith was best embodied in the outsize power Trump granted to Stephen Miller, a preternaturally aged millennial whose views toward immigration can best be summed up as “no.”

Under Miller’s aegis, the White House moved to not just punish people crossing the southern border but to limit legal immigration as well, including asylum claims and refugee admissions. The pandemic provided an all-new excuse to restrict entry into America, and Miller seized it gladly.

It was a set of policies designed by a man who trafficked in white nationalist dogma, sharing links to white supremacist websites in emails leaked in 2019. These sites and their followers share a general belief in the “great replacement” conspiracy theory, which claims that white people are intentionally being replaced by other races. Lately, figures like Fox News’ Tucker Carlson have said the quiet part out loud, directly telling audiences that Democrats are trying to replace Republican voters with migrants.

The solution, in the white nationalist mindset, is twofold: first, limit immigration, especially from undesirable countries in Africa and Asia; second, crank up the birthrate among whites — can’t overtake the white population if they’re churning out enough babies to offset the browning of America! This obsession with birthrates helps explain the misogyny often intertwined with white supremacy and the ties between these far-right groups and the anti-abortion movement.

But it’s not that easy to manufacture an increased fertility rate, as other countries such as Hungary and Poland have learned recently. Which leaves immigration as the method most within the grasp of public policy to change — and the method that is the most fraught in U.S. politics right now, thanks to the GOP’s constant agitation about security at the southern border.

It’s working for them in the short term to rally their extremely white base. But it’s wasting time that could be spent cushioning the U.S. against the economic strain that’s looming in our near future. And other countries aren’t going to be patient.

In 2009, I picked up the book “The Next 100 Years: A Forecast for the 21st Century,” by George Friedman. For all the more out-there predictions from Friedman, the one that’s stuck with me is his belief that “after 2050 advanced nations will need massive immigration to fill jobs and support their aging citizenry,” prompting major competition for this vital resource.

Daniel Griswold, a senior scholar with the libertarian Koch-funded Mercatus Center at George Mason University, more or less agrees. In December, he argued that after the losses incurred during Covid-19, Congress needs to move fast to head off these problems:

I’m inclined to agree. Most Democrats in Congress would, as well. Which leaves the GOP with a choice: Do they want to back the revanchist white supremacist movement and risk economic catastrophe? Or will they support the businesses that need the labor that immigrants provide?

Either way, they’d better make it soon — we’re not getting any younger over here.