Editor’s Note: This short read has been updated to correct Figure 1.
Repealing birthright citizenship for U.S. children born to unauthorized immigrants or certain other noncitizens would have a contrary result from its stated aim of reducing unauthorized immigration. In fact, as new estimates from the Migration Policy Institute (MPI) and Penn State’s Population Research Institute show, repeal would significantly swell the size of the unauthorized population—now and for generations to come.
The question of birthright citizenship has emerged periodically over the years. The debate was reignited in January when President Donald Trump signed an executive order on his first day back in office to end the grant of birthright citizenship to children born to certain noncitizens. The order, which has been stayed by the courts amid questions over its constitutionality, specifies that going forward, only children born to at least one U.S.-citizen or lawful permanent resident parent would automatically acquire U.S. citizenship.
New MPI-Penn State projections show that ending birthright citizenship for U.S.-born children with parents who are either unauthorized or are temporary immigrants (or a combination of the two) would increase the unauthorized population by an additional 2.7 million by 2045 and by 5.4 million by 2075. Each year, over the next 50 years, an average of about 255,000 children born on U.S. soil would start life without U.S. citizenship based on their parents’ legal status, the research shows.
These projections, which draw on an MPI-Penn State methodology for estimating the size and basic demographic characteristics of the U.S. unauthorized immigrant population, are conservative ones. (See below for a discussion of assumptions and Box 1 for the methods used to derive these projections.)
Beyond significantly adding to an unauthorized immigrant population that MPI estimates stood at 13.7 million as of mid-2023, the end of birthright citizenship for many children would create a self-perpetuating, multigenerational underclass—with U.S.-born residents inheriting the social disadvantage borne by their parents and even, over time, their grandparents and great-grandparents. By 2075, there would be 1.7 million U.S. born lacking citizenship or legal status who were the children of two parents who themselves had been born in the United States, the authors estimate.
This creation of a class of U.S.-born residents deprived of the rights that citizenship conveys to their neighbors, classmates, and work colleagues could sow the seeds for significant disruption to economic mobility and social cohesion in the years and decades ahead.
The Trump executive order, which has been temporarily blocked from implementation by three federal appeals courts, will get a hearing before the Supreme Court on May 15. Even as litigation over the order’s constitutionality continues, the high court will consider whether it can go forward nationally or in certain states only, and whether state attorneys general have standing to sue. Given the Supreme Court has scheduled the hearing with unusual speed and during a period when it does not usually hear cases, the date of the oral argument speaks to the gravity of the constitutional and presidential powers issues at stake.
A Policy Achieving Contrary Aims
Touted by its supporters as a means of reducing unauthorized immigration, ending the guarantee of citizenship bestowed on virtually every baby born on U.S. soil would generate a contrary result. (The significant exception has been the U.S.-born children of foreign diplomats, who do not acquire U.S. citizenship at birth.)
The MPI-Penn State analysis suggests that if birthright citizenship were withheld from children born to two parents who lacked either U.S. citizenship or lawful permanent residence (called “non-birthright parents” here), the unauthorized population would be 40 percent larger in 2075 than it would be under the current interpretation of birthright citizenship. The result would be that the “unauthorized” population (comprised of unauthorized immigrants as well as the U.S. born with non-birthright parents) would be 2.7 million higher in 2045 and 5.4 million higher in 2075 than if birthright citizenship was left unchanged.
Figure 1. Projected Increase in the U.S. Unauthorized Population with Birthright Citizenship Repeal, 2025-75
Notes: These estimates reflect not only the addition of U.S.-born “unauthorized” people (light teal) but also the researchers’ modeling of how the unauthorized immigrant population would evolve between 2025 and 2075, given assumptions of steady-state in-migration, deaths, return migration, and legalization (dark teal). The unauthorized immigrant population has been getting older and is therefore projected to decline from 13.7 million as of mid-2023 estimates to 12.1 million in 2045 and 11.6 million in 2075 due to deaths in the future. However, if birthright citizenship were repealed, the total “unauthorized” population, including both unauthorized immigrants and the U.S.-born “unauthorized” population, would rise from its mid-2023 estimate of 13.7 million to 14.8 million in 2045 and 17.1 million in 2075. For more on the aging of the unauthorized immigrant population, see Jennifer Van Hook and Mara Getz Sheftel, “The Growth and Diversity of Older Undocumented Immigrants in the United States,” Demography, forthcoming. Source: Migration Policy Institute (MPI) and Penn State Population Research Institute estimates.
These estimates account for the likely number of births to non-birthright parents each year (see below) and for the fact that not all children born to non-birthright parents will live out their lives in the United States. In fact, a steady stream of U.S.-born and immigrant children of immigrants leave the country each year, either on their own terms or because they or a family member were deported. For example, one study estimated that 500,000 U.S.-born children lived in Mexico as of 2020. For the purposes of their estimates, MPI and Penn State analysts and demographers assumed that if U.S.-born children of non-birthright parents are born as, essentially, unauthorized “immigrants,” they would leave the United States or legalize at the same rate as their parents (about 3.5 percent per year either leaving or legalizing).
This assumption could be wrong: U.S.-born children might stay in the United States at higher rates than their immigrant parents. If that was the case, the unauthorized population would grow even faster over the coming decades.
As noted, these estimates assume that in-migration and out-migration rates hold steady. But what would happen if the U.S. government managed to seal the border against illegal entries in an enduring manner and ramp up deportations? Or what if unauthorized immigrants leave in larger numbers because their children cannot obtain U.S. citizenship? Even assuming that nobody enters the country illegally after 2025 and return migration rates are double what they have been, changes to birthright citizenship would still result in an unauthorized population that is 1.3 million larger in 2045 than it would be under current rules and would remain 1.3 million larger in 2075.
Box 1.Methods
To model the effects of ending birthright citizenship, analysts from the Migration Policy Institute (MPI) and Penn State’s Population Research Institute estimated the number of births each year between 2025 and 2075 to two parents who are either unauthorized immigrants or on temporary visas (in other words not U.S. citizens or lawful permanent residents, also known as green-card holders), or a combination of both.
The researchers started with the MPI estimate of the (1) unauthorized immigrant and (2) temporary visa-holding populations in 2023, the most recent year for which such imputations can be made based on availability of data from the U.S. Census Bureau’s American Community Survey (ACS). The temporary visa-holding population represents individuals chiefly on student or work visas (such as the H-1B or the O or L visas). This temporary visa population also includes a small number of people resettled as refugees or granted asylum who have not yet adjusted to lawful permanent residence (LPR status, also known as getting a green card).
The analysts further calculated how large the population of U.S.-born children of non-birthright parents would be in future years if current rates of in-migration, out-migration, deaths, and fertility held steady through 2075.
For more information on the methodology, click here.
Births to Non-Birthright Parents
A different way to view the number of people affected by a major change to birthright citizenship is to look at how many babies would be born in the United States without U.S. citizenship, even if they did not stay in the United States into adulthood or if they later obtained U.S. legal status by another means or died.
The MPI-Penn State analysis shows an average 222,000 children will be born each year to non-birthright immigrant parents over the next 50 years. This would translate to 4.7 million births to non-birthright immigrant parents between now and 2045, and 11.1 million by 2075. As noted, though, these would not represent a 1:1 increase in the overall unauthorized population, as the analysis incorporates assumptions regarding emigration, deaths, and the ability to receive legal status.
Adding in the number of births to U.S.-born “unauthorized” parents, these numbers would be even larger: 4.8 million births by 2045 and 12.8 million by 2075. This would bring overall average births to non-birthright parents, U.S. born and immigrant alike, to 255,000 annually.
Not all of these children would live out their lives in the United States as unauthorized residents. Some would leave for the home country of their parents or grandparents, where they might have citizenship. And others would find a way to gain legal status in the United States, such as through derivative status from a parent who is a temporary visa holder or through later marriage to a U.S. citizen or other immigration pathway. But all would be born without the full rights of U.S. citizenship.
Destabilizing Effects
The creation of this new class of socially excluded persons would have profound social and economic impacts. U.S.-born “unauthorized” individuals would be unable to work legally, access economic supports in times of need, receive in-state tuition or financial aid for higher education in many states, or participate fully in society, hampering their ability to contribute to their fullest potential. Depriving U.S.-born children of full membership in society would also threaten to undermine the country’s exemplary record of integrating immigrant families, in which the children of immigrants regularly surpass their parents’ educational attainment, income, English proficiency, and other markers of success.
At a time of unprecedented population aging and with immigrants and their U.S.-born children already driving all labor force growth, the inability of this population to work legally and therefore to use its educational investments in professional careers would generate a growing group of workers relegated to low-wage jobs, and stunt the country’s economic growth.
Separately, repeal would carry significant administrative costs and sow confusion. Repeal of automatic birthright citizenship would mean abandoning a simple, “bright line” rule for determining citizenship and exchanging it for one that is far harder to implement and that would impose paperwork burdens on citizens, hospitals, and government agencies alike.
Other Means to Address “Birth Tourism”
Advocates for repeal often cite “birth tourism”—foreign women coming to the United States for the purpose of giving birth to secure U.S. citizenship for their baby—to justify denying citizenship to children of immigrants who do not have permanent residency. However, empirical data show that this phenomenon is rare.
Births to nonresident, foreign mothers account for a tiny fraction of U.S. births: About 9,000 of the 3.6 million U.S. births that occur every year, according to the U.S. Centers for Disease Control and Prevention. There are targeted measures, including visa enforcement and airline screening, that offer more effective and proportional responses than repealing a right enshrined in the Constitution in 1868 with the 14th Amendment and endorsed in 1898 by the Supreme Court.
A “Solution” Worse than the Problem
Repealing the guarantee of automatic birthright citizenship for virtually all babies born on U.S. soil would create a legally and socially excluded class of Americans, with societal and economic effects spanning generations. This perpetuation of hereditary disadvantage based on the legal status of one’s ancestors would be unprecedented in U.S. immigration law and would be contrary to the American sense of fair play that has rejected visiting the sins of the parents on the children.
Even setting aside these very significant issues, at a policy level, repeal of birthright citizenship not only does not address the problem it is purported to solve but actually has a contrary effect. Withholding U.S. citizenship from babies born in the United States to parents who are unauthorized immigrants or temporary visa holders would swell the U.S. unauthorized population by 2.7 million as of 2045 and by 5.4 million as of 2075.
The demographic results of repeal then run counter to this extraordinary measure’s intended purpose: reducing the size of the unauthorized immigrant population. The creation of such a multigenerational underclass, with disadvantage passed from generation to generation, would represent a stark departure from core principles of American law, tradition, and justice.
Repealing Birthright Citizenship Would Significantly Increase the Size of the U.S. Unauthorized Population
Editor’s Note: This short read has been updated to correct Figure 1.
Repealing birthright citizenship for U.S. children born to unauthorized immigrants or certain other noncitizens would have a contrary result from its stated aim of reducing unauthorized immigration. In fact, as new estimates from the Migration Policy Institute (MPI) and Penn State’s Population Research Institute show, repeal would significantly swell the size of the unauthorized population—now and for generations to come.
The question of birthright citizenship has emerged periodically over the years. The debate was reignited in January when President Donald Trump signed an executive order on his first day back in office to end the grant of birthright citizenship to children born to certain noncitizens. The order, which has been stayed by the courts amid questions over its constitutionality, specifies that going forward, only children born to at least one U.S.-citizen or lawful permanent resident parent would automatically acquire U.S. citizenship.
New MPI-Penn State projections show that ending birthright citizenship for U.S.-born children with parents who are either unauthorized or are temporary immigrants (or a combination of the two) would increase the unauthorized population by an additional 2.7 million by 2045 and by 5.4 million by 2075. Each year, over the next 50 years, an average of about 255,000 children born on U.S. soil would start life without U.S. citizenship based on their parents’ legal status, the research shows.
These projections, which draw on an MPI-Penn State methodology for estimating the size and basic demographic characteristics of the U.S. unauthorized immigrant population, are conservative ones. (See below for a discussion of assumptions and Box 1 for the methods used to derive these projections.)
Beyond significantly adding to an unauthorized immigrant population that MPI estimates stood at 13.7 million as of mid-2023, the end of birthright citizenship for many children would create a self-perpetuating, multigenerational underclass—with U.S.-born residents inheriting the social disadvantage borne by their parents and even, over time, their grandparents and great-grandparents. By 2075, there would be 1.7 million U.S. born lacking citizenship or legal status who were the children of two parents who themselves had been born in the United States, the authors estimate.
This creation of a class of U.S.-born residents deprived of the rights that citizenship conveys to their neighbors, classmates, and work colleagues could sow the seeds for significant disruption to economic mobility and social cohesion in the years and decades ahead.
The Trump executive order, which has been temporarily blocked from implementation by three federal appeals courts, will get a hearing before the Supreme Court on May 15. Even as litigation over the order’s constitutionality continues, the high court will consider whether it can go forward nationally or in certain states only, and whether state attorneys general have standing to sue. Given the Supreme Court has scheduled the hearing with unusual speed and during a period when it does not usually hear cases, the date of the oral argument speaks to the gravity of the constitutional and presidential powers issues at stake.
A Policy Achieving Contrary Aims
Touted by its supporters as a means of reducing unauthorized immigration, ending the guarantee of citizenship bestowed on virtually every baby born on U.S. soil would generate a contrary result. (The significant exception has been the U.S.-born children of foreign diplomats, who do not acquire U.S. citizenship at birth.)
The MPI-Penn State analysis suggests that if birthright citizenship were withheld from children born to two parents who lacked either U.S. citizenship or lawful permanent residence (called “non-birthright parents” here), the unauthorized population would be 40 percent larger in 2075 than it would be under the current interpretation of birthright citizenship. The result would be that the “unauthorized” population (comprised of unauthorized immigrants as well as the U.S. born with non-birthright parents) would be 2.7 million higher in 2045 and 5.4 million higher in 2075 than if birthright citizenship was left unchanged.
Figure 1. Projected Increase in the U.S. Unauthorized Population with Birthright Citizenship Repeal, 2025-75
Notes: These estimates reflect not only the addition of U.S.-born “unauthorized” people (light teal) but also the researchers’ modeling of how the unauthorized immigrant population would evolve between 2025 and 2075, given assumptions of steady-state in-migration, deaths, return migration, and legalization (dark teal). The unauthorized immigrant population has been getting older and is therefore projected to decline from 13.7 million as of mid-2023 estimates to 12.1 million in 2045 and 11.6 million in 2075 due to deaths in the future. However, if birthright citizenship were repealed, the total “unauthorized” population, including both unauthorized immigrants and the U.S.-born “unauthorized” population, would rise from its mid-2023 estimate of 13.7 million to 14.8 million in 2045 and 17.1 million in 2075. For more on the aging of the unauthorized immigrant population, see Jennifer Van Hook and Mara Getz Sheftel, “The Growth and Diversity of Older Undocumented Immigrants in the United States,” Demography, forthcoming.
Source: Migration Policy Institute (MPI) and Penn State Population Research Institute estimates.
These estimates account for the likely number of births to non-birthright parents each year (see below) and for the fact that not all children born to non-birthright parents will live out their lives in the United States. In fact, a steady stream of U.S.-born and immigrant children of immigrants leave the country each year, either on their own terms or because they or a family member were deported. For example, one study estimated that 500,000 U.S.-born children lived in Mexico as of 2020. For the purposes of their estimates, MPI and Penn State analysts and demographers assumed that if U.S.-born children of non-birthright parents are born as, essentially, unauthorized “immigrants,” they would leave the United States or legalize at the same rate as their parents (about 3.5 percent per year either leaving or legalizing).
This assumption could be wrong: U.S.-born children might stay in the United States at higher rates than their immigrant parents. If that was the case, the unauthorized population would grow even faster over the coming decades.
As noted, these estimates assume that in-migration and out-migration rates hold steady. But what would happen if the U.S. government managed to seal the border against illegal entries in an enduring manner and ramp up deportations? Or what if unauthorized immigrants leave in larger numbers because their children cannot obtain U.S. citizenship? Even assuming that nobody enters the country illegally after 2025 and return migration rates are double what they have been, changes to birthright citizenship would still result in an unauthorized population that is 1.3 million larger in 2045 than it would be under current rules and would remain 1.3 million larger in 2075.
Box 1. Methods
To model the effects of ending birthright citizenship, analysts from the Migration Policy Institute (MPI) and Penn State’s Population Research Institute estimated the number of births each year between 2025 and 2075 to two parents who are either unauthorized immigrants or on temporary visas (in other words not U.S. citizens or lawful permanent residents, also known as green-card holders), or a combination of both.
The researchers started with the MPI estimate of the (1) unauthorized immigrant and (2) temporary visa-holding populations in 2023, the most recent year for which such imputations can be made based on availability of data from the U.S. Census Bureau’s American Community Survey (ACS). The temporary visa-holding population represents individuals chiefly on student or work visas (such as the H-1B or the O or L visas). This temporary visa population also includes a small number of people resettled as refugees or granted asylum who have not yet adjusted to lawful permanent residence (LPR status, also known as getting a green card).
The analysts further calculated how large the population of U.S.-born children of non-birthright parents would be in future years if current rates of in-migration, out-migration, deaths, and fertility held steady through 2075.
For more information on the methodology, click here.
Births to Non-Birthright Parents
A different way to view the number of people affected by a major change to birthright citizenship is to look at how many babies would be born in the United States without U.S. citizenship, even if they did not stay in the United States into adulthood or if they later obtained U.S. legal status by another means or died.
The MPI-Penn State analysis shows an average 222,000 children will be born each year to non-birthright immigrant parents over the next 50 years. This would translate to 4.7 million births to non-birthright immigrant parents between now and 2045, and 11.1 million by 2075. As noted, though, these would not represent a 1:1 increase in the overall unauthorized population, as the analysis incorporates assumptions regarding emigration, deaths, and the ability to receive legal status.
Adding in the number of births to U.S.-born “unauthorized” parents, these numbers would be even larger: 4.8 million births by 2045 and 12.8 million by 2075. This would bring overall average births to non-birthright parents, U.S. born and immigrant alike, to 255,000 annually.
Not all of these children would live out their lives in the United States as unauthorized residents. Some would leave for the home country of their parents or grandparents, where they might have citizenship. And others would find a way to gain legal status in the United States, such as through derivative status from a parent who is a temporary visa holder or through later marriage to a U.S. citizen or other immigration pathway. But all would be born without the full rights of U.S. citizenship.
Destabilizing Effects
The creation of this new class of socially excluded persons would have profound social and economic impacts. U.S.-born “unauthorized” individuals would be unable to work legally, access economic supports in times of need, receive in-state tuition or financial aid for higher education in many states, or participate fully in society, hampering their ability to contribute to their fullest potential. Depriving U.S.-born children of full membership in society would also threaten to undermine the country’s exemplary record of integrating immigrant families, in which the children of immigrants regularly surpass their parents’ educational attainment, income, English proficiency, and other markers of success.
At a time of unprecedented population aging and with immigrants and their U.S.-born children already driving all labor force growth, the inability of this population to work legally and therefore to use its educational investments in professional careers would generate a growing group of workers relegated to low-wage jobs, and stunt the country’s economic growth.
Separately, repeal would carry significant administrative costs and sow confusion. Repeal of automatic birthright citizenship would mean abandoning a simple, “bright line” rule for determining citizenship and exchanging it for one that is far harder to implement and that would impose paperwork burdens on citizens, hospitals, and government agencies alike.
Other Means to Address “Birth Tourism”
Advocates for repeal often cite “birth tourism”—foreign women coming to the United States for the purpose of giving birth to secure U.S. citizenship for their baby—to justify denying citizenship to children of immigrants who do not have permanent residency. However, empirical data show that this phenomenon is rare.
Births to nonresident, foreign mothers account for a tiny fraction of U.S. births: About 9,000 of the 3.6 million U.S. births that occur every year, according to the U.S. Centers for Disease Control and Prevention. There are targeted measures, including visa enforcement and airline screening, that offer more effective and proportional responses than repealing a right enshrined in the Constitution in 1868 with the 14th Amendment and endorsed in 1898 by the Supreme Court.
A “Solution” Worse than the Problem
Repealing the guarantee of automatic birthright citizenship for virtually all babies born on U.S. soil would create a legally and socially excluded class of Americans, with societal and economic effects spanning generations. This perpetuation of hereditary disadvantage based on the legal status of one’s ancestors would be unprecedented in U.S. immigration law and would be contrary to the American sense of fair play that has rejected visiting the sins of the parents on the children.
Even setting aside these very significant issues, at a policy level, repeal of birthright citizenship not only does not address the problem it is purported to solve but actually has a contrary effect. Withholding U.S. citizenship from babies born in the United States to parents who are unauthorized immigrants or temporary visa holders would swell the U.S. unauthorized population by 2.7 million as of 2045 and by 5.4 million as of 2075.
The demographic results of repeal then run counter to this extraordinary measure’s intended purpose: reducing the size of the unauthorized immigrant population. The creation of such a multigenerational underclass, with disadvantage passed from generation to generation, would represent a stark departure from core principles of American law, tradition, and justice.