People riding the ferry to Ellis Island for a naturalization ceremony on Citizenship Day past the Statue of Liberty in New York.

Editor’s Note: Justin Gest (@_Justin Gest) is a professor at George Mason University’s Schar School of Policy and Government, where he directs the Public Policy program. He is the author of six books on the politics of immigration and demographic change, including his newest, “Majority Minority.” Read more opinion at CNN.

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Last week, President Joe Biden committed a diplomatic faux pas when he chided India and Japan, two critical US allies, for being “xenophobic.” Attributing America’s success to its historic openness to immigration, the president suggested that Delhi and Tokyo’s aversion to foreigners constrained their economic growth and population stability.

Justin Gest

Tactless as it may have been, Biden was not wrong. Japan, in particular, is expected to see its population drop by a third in the next half-century.

But a few months ago, the US Census Bureau released new projections showing that America’s own population will — for the first time ever — shrink after 2080.

Only one thing is preventing the nation from reaching this milestone next year: immigration.

The consistent arrival of newcomers is expected to keep America from aging as rapidly as Japan and other major economies. If immigration opponents were to cut annual admissions in half, the US would start to shrink in 2044.

All countries’ populations change with trends in birth rates and life expectancy. And like many high-income nations, the US has witnessed a drop in fertility over the last half-century. Combined with longer life expectancy, this has contributed to severe demographic aging.

Aging is problematic for two reasons. It promises insolvency when too few working-age people pay into pension and health care funds that have obligations to support higher numbers of retirement-age seniors. Population decline also spells the decline of economic power and market size — one of America’s greatest geopolitical assets.

The primary demographic antidote for low fertility is immigration. Disproportionately working age and reaching higher fertility rates, immigrants inject youth, labor and innovation into societies, and — at high enough numbers — they offset aging trends. As Biden touted, this has been a core part of America’s economic growth over the last few decades, but also our demographic stability. Nearly all US population increases have been attributable to immigrant arrivals, as opposed to births outpacing deaths.

What makes the new Census Bureau projections especially bleak is that the shrinkage is expected to take place even if the US government keeps immigrant admissions at their present levels. And in case you haven’t downloaded Truth Social, present levels are unacceptable to today’s Republican Party.

In an interview with Time magazine published last week, former President Donald Trump said he wants to place new arrivals in detention camps and deport millions of immigrants that Census projections assume will otherwise remain in the US — both of which will only hasten our country’s demographic decline.

According to the Census report, the number of Americans over 64 years old will surpass the number of Americans under 18 by 2029. At that point, only 60% of the US population will be between 18 and 64 — down from close to 70% in 2010. Deaths in America are projected to outpace births by 2038 for the first time ever. At that point, there will be 13,000 more deaths than births in the US, but the shortfall increases to 1.2 million more deaths annually by 2100 — double the annual shortfall in Japan today.

The US population is projected to reach a high of nearly 370 million in 2080 before beginning its historic downward turn. But if immigration were to be cut approximately in half, Census Bureau demographers estimate that this milestone would occur in 2044. If borders close completely, as many Republican public officials advocate, the decline would start next year.

The immediacy of this impact should not be surprising. If US population growth is attributable to immigrant arrivals, which it now is, then America will cease to grow when no newcomers are admitted.

Of course, Republicans’ self-defeating anxiety around immigration is informed, to some extent, by an earlier Census report — the March 2015 release that anticipated a “majority minority” milestone in 2044. Unlike the new study, the projected decline of America’s “White” population to an under-50% share of the population made headlines everywhere. The numbers — which are problematic for numerous reasons — both emboldened liberals about their electoral prospects and generated fierce backlash to immigration among conservatives.

Once a bureaucratic matter so insignificant to conservatives that the Reagan administration endorsed amnesty for all undocumented foreigners, immigration has now become the central pillar of the post-2015 Republican Party. Immigration is the top issue priority for conservatives entering the 2024 general election, and a hindrance for Biden’s prospects among independents.

But if the 2015 Census projections inflamed anti-immigrant sentiment, the recent report might have the opposite effect.

That’s because my newest research suggests that information about the realities of demographic aging persuades people — especially moderates and centrists — to open their minds about immigration.

My coauthors and I surveyed more than 20,000 adults across 19 European countries. A subset of these respondents was informed about real demographic trends, much like those revealed by the recent US Census report according to demographers, birth rates in their country “are significantly below the level needed to maintain the native population.”

The same subset of respondents was also told that, even though many immigrants have already entered their country over the years, to maintain current population levels, the government will need to accept “significantly more immigrants from countries outside of Europe with higher birth rates, such as Muslim-majority and African countries.”

Remarkably, despite the invocation of the minority outgroups that rankle some voters, respondents in the subset were more likely to support increased immigration numbers than those who were not exposed to the news about demographic decline at all.

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    In Western European countries — where elevated minority fertility rates are tempering the effects of demographic aging — respondents were even resistant to far-right fearmongering narratives about “replacement theory” after immigration was portrayed as critical to the nation’s endurance. This was especially true for respondents with centrist political ideologies, those who were over 35 years old and those with average educational backgrounds.

    Rather than see immigrants as a threat to “replace” the nation, these respondents grew more likely to see them as a way to “replenish” the nation.

    The findings from this experiment and the Census Bureau report emerge at a moment when American and European political leaders are scrambling to fortify their borders. But just as people want a well-managed admissions system, there is a countervailing desire to sustain the national population.

    As much as the world polarizes over foreigners’ arrival, demographic aging is an unwavering, intensifying reality that remains unaddressed, and a good reason to invest in an orderly immigration system that sustains the nation into the future.