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Imagine you are pregnant. You live in Texas and will be giving birth this summer. Meanwhile, your friend is also pregnant and is scheduled to have her baby the very same day as you—except she lives in Maryland. Both of you are either undocumented or on a temporary visa, but because you live in Texas your newborn may be ineligible to receive U.S. citizenship, rendering them stateless. Over in Maryland, your friend’s baby will become a U.S. citizen, benefiting from social services only offered to people with a Social Security number.

You’re probably wondering: How is that fair?

It’s a scenario that the Supreme Court is grappling with as it deliberates on Trump v. CASA , a case that will determine the lawfulness of the three nationwide injunctions currently preventing President Donald Trump’s birthright citizenship executive order from taking effect. Last week, the federal government argued it wants to limit those injunctions to only the plaintiffs suing—22 states and Washington, D.C., two immigrant rights groups, and four pregnant women—because it believes lower courts should not have universal authority to dictate the executive branch’s policy.

If the justices rule in favor of Trump, it could create a world in which babies born to undocumented immigrants (and those here on temporary visas) in nearly half of U.S. states would not receive birthright citizenship. That’s despite many of the justices suggesting that Trump’s executive order, on its merits, is most likely unconstitutional. But that’s not the issue they’ve tasked themselves with solving for now; instead, they accepted the Trump administration’s request to exclusively consider the scope of three nationwide injunctions issued against the policy.

I talked to Elora Mukherjee, clinical law professor at Columbia University and director of the school’s Immigrants’ Rights Clinic, to understand how the president’s executive order would work in practice, if the justices rule that the current nationwide injunctions cannot stand and must be limited to the plaintiffs.

Our conversation has been edited and condensed for clarity.

Elora Mukherjee: The administration has purposely avoided arguing to the Supreme Court that its interpretation of the 14 ^th Amendment is correct, because it knows it would lose that question on the merits. But a ruling from the Supreme Court that the nationwide injunction can’t stand would nevertheless have dramatic and far-reaching consequences. The executive order ending birthright citizenship could be enforced in some states, while remaining states could block it, and that would create a fragmented and chaotic citizenship across the country.

And as you’re suggesting, babies born on the same day could be citizens in one state, but stateless in the other. That would destabilize families, overwhelm local governments, and invite a flood of costly legal battles. In terms of whether a pregnant person could cross state lines before giving birth, maybe. They could, but that would privilege pregnant people who have access to resources, information about the legal system, a place to stay once they cross state lines so that they can give birth safely, and medical care once they do so. For many people with limited resources, it won’t be possible to cross state lines.

New Jersey Solicitor General Jeremy Feigenbaum was explaining to the court that every year, about 6,000 babies cross state lines and come into the state of New Jersey, and the state needs to do citizenship verification for all of those babies. Justice Sotomayor chimed in and noted it’s not just the state of New Jersey; it would be the same in the 22 states collectively that are participating in this litigation and challenging the executive order. Feigenbaum agreed and explained that a lack of nationwide injunctive relief in citizenship would undermine the ability of the plaintiff states to process benefits for eligible children and families. The federal government requires Social Security numbers to be provided for the administration of benefits. Babies born outside of the plaintiff states might arrive in a plaintiff state without a Social Security number, and the burden would be on the plaintiff state to figure out how to administer benefits.

Plaintiff states would also incur substantially more costs to get them enrolled, as Feigenbaum argued. As a nation, we haven’t had citizenship turn on crossing states since the Civil War, and it’s not clear how this would work on the ground at all.

Knowing that the Trump administration is in the midst of an aggressive immigration crackdown, is it possible that a baby born in a plaintiff state who then travels to a non-plaintiff state could end up being subject to arrest, detention, and even deportation?

It is certainly conceivable that the executive branch, Immigrations and Customs Enforcement, and others at the highest echelons of our executive branch, once a baby crosses state lines, they may lose their U.S. citizenship. We can imagine that a baby is born in Maryland, one of the plaintiff states that’s covered by an injunction right now, and they move to Texas. They may be subject to immigration enforcement actions, correctly or incorrectly, maybe due to racial profiling or something else. Once that baby is arrested on the way to being deported from the United States, how will that baby explain that they were actually granted U.S. citizenship in Maryland?

What we’ve seen is an executive branch that is intent on rapidly deporting people from the United States without offering them any meaningful due process. We’ve already had many hundreds of people wrongly deported from the United States since Jan. 20, and U.S. citizens are regularly deported wrongly from the United States already. If the executive order is not enjoined nationwide, the risk of error dramatically multiplies.

In that scenario, would the families of babies who are born in plaintiff states but who move to, or even just visit, a non-plaintiff state where their U.S. citizenship is not recognized have grounds to sue the federal government over that inconsistency?

Absolutely. Justice Jackson described this as a “catch-me-if-you-can regime” that would be inconsistent with the rule of law. Those who would be left most vulnerable would be families without sufficient legal resources, not as well-off, not fluent in English, or those who don’t have access to their communities. It would be those who are most vulnerable who would be affected, because they can’t run to federal court to prove that their baby actually is a U.S. citizen.

In the infamous Dred Scott case, the Supreme Court ruled that enslaved people were not considered American citizens, even if they lived in a state that had outlawed slavery. Are we facing a similar situation with U.S. citizenship?

The current situation echoes the worst vestiges of Dred Scott . He was a Black man born into slavery and eventually moved to a free state. He was then brought back to a state where slavery was legal, and abolitionist lawyers filed suit on his behalf, explaining that because he had spent time in a free state, he was now a free man and should be recognized as a free U.S. citizen. In that case, Justice Taney reached two major rulings. First, that the federal court did not have jurisdiction to hear Scott’s case because African Americans were not considered U.S. citizens. It was a moment in time when citizenship varied based on crossing state lines, and in the Dred Scott v. Sandford decision, Justice Taney held that if citizenship can vary based on crossing state lines, then Black people are not citizens at all.

An extension of that decision was in the Prigg v. Pennsylvania case, which involved a family that had escaped slavery and had settled in Pennsylvania. A slave catcher from a state that permitted slavery came into Pennsylvania, caught the family, and sent them back into slavery.

We can imagine that if there is a patchwork of U.S. citizenship in the United States today, if the executive order is not subject to a nationwide injunction, there could be inconsistent rulings about whether a deportation order is enforceable based on the state that a person is currently in. A patchwork of citizenship would be extremely harmful and simply not administrable.

What should families who potentially stand to be impacted by the president’s executive order do if the justices ultimately rule the nationwide injunctions are unconstitutional?

I think it’s important to highlight that birthright citizenship is a core part of what it means to be an American. It’s a guarantee that all children who are born here are equal under the law. A ruling that weakens the current nationwide injunctions would not only gut the 14 ^th Amendment’s promise of equal citizenship, but it would tear at the core of America’s national identity. Regardless of what the court might intend, if it doesn’t let the nationwide injunction stand, a ruling against the injunction would be understood as a ruling in favor of ending birthright citizenship. It would be claimed by the executive branch as a victory.

I also think it’s worth noting that Solicitor General John Sauer did concede that if the executive order is allowed to go into effect, in part, there would be a 30-day period before the order takes effect. During that period, I would expect that pregnant families would likely file class-action litigation under Rule 23 to try to have the executive order enjoined on a classwide basis.

I would also advise, during that period, that all expecting parents move to a state where they would be able to give birth to U.S. citizens. Those who remain in other states may give birth to children who are literally stateless, and that will pose complications for those babies throughout their lives.