https://www.fcd-us.org/how-empirical-research-unquestionably-supports-birthright-citizenship/
I have spent years studying how immigration policy shapes the lives of children and families. So, when the opportunity arose to lead an amicus brief submitted to the Supreme Court of the United States in a case that could redefine birthright citizenship, I knew the stakes could not be higher. This was a chance to bring evidence directly into a space that will determine the futures of millions of children.
Birthright Citizenship’s Constitutional Foundation
Birthright citizenship is grounded in the 14th Amendment, ratified in 1868 in the wake of the Civil War. Its Citizenship Clause affirms that all persons born on U.S. soil are citizens, a principle intended to ensure that no child would be excluded from belonging because of their parentage. The amendment deliberately rejected systems that excluded entire groups and was designed to prevent the creation of a permanent, hereditary underclass.
Today, that safeguard is being tested.
Why an Amicus Brief
As empirical scholars, our task is to produce rigorous, objective, peer-reviewed knowledge. This also means we may be called upon as experts in legal cases, including those that can shape constitutional interpretation.
An amicus brief, or “friend of the court” brief, allows researchers and experts to provide context, evidence, and analyses that extend beyond the arguments presented by the parties in a case. In this instance, our goal was clear: to ensure that the Court had access to the best available evidence about what birthright citizenship does, who it affects, and what would happen if it were curtailed.
This brief reflects the consensus of a broad network of scholars from across disciplines and institutions, including economists, sociologists, demographers, public health, and public policy researchers. Colleagues, including Catalina Amuedo-Dorantes, Peter Catron, Philip Connor, Chloe East, Erin Hamilton, Amy Hsin, Cecilia Menjivar, Rob Smith, Jenny Van Hook, Hirokazu Yoshikawa, and Maria-Elena Young, brought years of research and expertise to bear on a shared question. Over 130 other scholars from multiple disciplines co-signed the brief.
This work reflects something larger than any single contribution. It is an example of how litigation often requires multi- and interdisciplinary evidence to document the real and potential harms or benefits of proposed or enacted policies.
Working collaboratively across disciplines and alongside legal advocates required us to translate complex research into clear, accessible evidence for a high-stakes context. It reinforced something I have long believed: that public policy must be shaped by evidence and not politics.
What the Data Shows
One of the central contributions of the brief is to quantify the scale of what is at stake.
If birthright citizenship were limited or reinterpreted as the Executive Order indicates, an estimated 4.8 million children born in the United States over the next two decades (and 12.8 million children by 2075!) could be denied citizenship. These children would grow up in the United States, but without the full rights and protections that citizenship provides. This would not be a marginal shift, but a fundamental restructuring of belonging by creating a heritable, intergenerational system of forced inequality — precisely the harm the 14th Amendment was designed to prevent.
Ending birthright citizenship would also be immensely costly. Indeed, our brief shows that under the status quo (i.e., current framework), birthright citizenship is projected to contribute approximately $7.7 trillion to the U.S. economy by 2074. These contributions reflect decades of participation in the country’s economic and civic life, challenging the assertion that immigrants are temporary or disconnected from the United States.
Our analysis also draws on a wide body of peer-reviewed research, built over decades by scholars across multiple disciplines. Taken together, this work offers a clear and consistent picture: the children of immigrants, regardless of their parents’ legal status, have deep and enduring ties to the country. They grow up here, raise children, build communities, and contribute in ways that include and extend beyond economic measures. Denying them citizenship would be harmful to individuals and to the country across multiple domains, including but not limited to education, employment, and health.
Confronting Persistent Myths
The brief also confronted some harmful myths about immigrant communities. For example, arguments against birthright citizenship tend to rely on unsubstantiated claims — phrases like “birth tourism” or suggestions that immigrant parents are exploiting the system without real ties to the United States. However, those narratives bear little resemblance to the research on these topics.
What the literature actually reveals is a story of parents who have lived here for years, building lives and routines in the same neighborhoods as any other family, sending their children to local schools, forming relationships with neighbors, coworkers, and communities. It is a story of children growing up with the US as their only home, shaped by the same institutions, expectations, and aspirations as their peers. The studies synthesized in our brief consistently reflect these realities of long-term residence, family stability, and deep community ties.
Addressing misconceptions with rigorous research was a critical part of our work. It was so important to use real evidence to challenge narratives that obscure what that data represents: real people, living real lives, already woven into the fabric of this country.
What Is at Stake for Children
At its core, this case is about children.
Research across disciplines has documented the benefits of citizenship for children, including improved educational outcomes, greater economic mobility, and enhanced well-being. Conversely, the absence of legal status is associated with a range of harms, many of which extend across generations. In some cases, children could be left without clear legal status in any country. To deny citizenship to millions of children born in the United States is to place them in a position of structural vulnerability from the very beginning of their lives, limiting opportunity, stability, and certainty.
The Executive Order would create a population that is born and raised in the United States but denied full social and political membership — thus echoing the very conditions that the 14th Amendment was designed to eliminate. It would formalize a system in which exclusion is inherited rather than imposed in isolated instances.
Conclusion
The 14th Amendment articulated a vision of belonging that was both simple and profound: that those born here are part of this nation. The question now is whether that vision will endure. The case challenging birthright citizenship is therefore about so much more than immigration; it is about how we will define ourselves as a country. Indeed, the Court’s decision will shape so much more than legal precedent: it will shape the lives of millions of children, and the meaning of a promise made generations ago.
The views and opinions expressed are those of the authors and do not necessarily reflect the views or positions of the Foundation.