The Supreme Court will soon rule on the citizenship status of the roughly 260,000 babies born on U.S. soil each year to illegal immigrants and visa holders — children who would no longer qualify for automatic citizenship under President Donald Trump’s executive order. Trump v. Barbara has been hotly contested by the public and pundits — a whole cast of self-appointed constitutional scholars has sprung up over recent cases — but far too few, I believe, have examined the math.
The dispute is over an executive order — to be upheld or, more likely, struck down — that Trump signed on his first day back in office. Since the Fourteenth Amendment, the rule has been simple: Born on U.S. soil? Congratulations, you’re a citizen, irrespective of your parents’ status. Trump’s order seeks to change that, directing federal agencies to cease recognizing citizenship for a child born here if the mother is either unlawfully present or only temporarily present on a visa, and if the father is not a citizen or green-card holder.
If upheld, this would affect the aforementioned 260,000 babies a year, according to the Pew Research Center. The composition is notable: Contrary to popular narratives, the overwhelming majority — roughly 240,000 — are children of mothers living here illegally. Only about 20,000 are children of mothers with legal temporary status. So the visa families who dominate the headlines are a small share, under 10% of the total. By raw count, then, this is overwhelmingly a policy affecting Hispanic migration: in fact, Latinos would be 80% of affected births today.
The visa subset, however, is affected almost across the board, with the order sparing only a few narrow exceptions. Because Trump’s order denies citizenship to children born to legal but temporary visa holders — and because many Asian immigrants spend years in the United States on F-1 or H-1B visas while awaiting green cards — the policy would fall hardest on them relative to population size. It would affect roughly 41 births per 1,000 undocumented Asian residents, compared with only 17 per 1,000 undocumented Latino residents. Strip the temporary visa provision, and the Asian figure drops to just 8 per 1,000. This provision matters: It captures nearly every birth to a legal temporary-visa couple.
Setting aside the annual numbers, what does this entail over the long run? It would be helpful, but not monumental. The roughly 245,000 births a year are dwarfed by, say, the 3.2 million border encounters in 2023. The border is the real long-term threat; rejecting birthright citizenship should be viewed primarily as a means of restoring some meaning to the words “American citizen.”
The population model splits into two depending on what transpires in the coming minutes. If we hold fertility, migration, and deportation rates constant — and keep birthright citizenship — the undocumented population declines as the existing cohort ages: 13.7 million in 2023, to roughly 12.1 million by 2045, to 11.6 million by 2075. Ironically but not surprisingly, if we end it, then this population rises considerably, to about 14.8 million by 2045 and 17.1 million by 2075. Even at double the current deportation rate, and with a perfectly sealed border, the 2045 figure stays roughly 1.3 million above the “keep-birthright” baseline.
THE POPULIST IMMIGRATION CIRCUS
All of these numbers rest on loose estimates and assume variables hold constant — many of which almost certainly won’t. So take the exact numbers with a healthy grain of salt, they are flawed, but do entertain the underlying idea: Ending birthright citizenship would likely drastically increase the illegal population of our country, even if we literally doubled down on deportations.
And even if you find that preferable to these people becoming legal members of society, this outcome carries enormous costs of its own. It would, in effect, manufacture a permanent underclass — millions of people working off the books, paying less into the system than legal and American workers would, suppressing wages in the industries where they cluster, and yet still owed a narrow but costly set of publicly funded amenities. This dystopian limbo is pleasant for neither them nor us. With some luck, these are problems we’ll get to have.