Last Thursday, the Trump administration asked the Supreme Court to step in and reverse three national injunctions against the president’s executive order ending birthright citizenship. One of these lawsuits was joined by North Carolina’s attorney general, Jeff Jackson, and I have written about that interesting case in a previous piece for the Carolina Journal. Importantly, the federal Justice Department is not asking the Supreme Court to weigh in on the merits of the birthright citizenship question. Rather, it has requested that the court rule on whether national injunctions in general are lawful.

National (or “universal”) injunctions are court orders that prevent a government from enforcing its policies against anyone, regardless of whether they were a party to the original lawsuit. These sweeping orders have been hotly debated for several years and have increased dramatically during President Donald Trump’s second term.

According to the Justice Department’s brief in the appeal, “District courts have issued more universal injunctions and TROs during February 2025 alone than through the first three years of the Biden Administration.”

The court will weigh many competing factors in deciding whether national injunctions are constitutional, but there is one unexpected element that may play a key role: Roman law.

The founding generation disliked the immense power that the Roman Empire gave its chief legal official (known as the “praetor”). Thomas Jefferson famously wrote that if judges are given “pr[a]etorian discretion, . . . the whole legal system becomes [un]certain.” Thus, it might be helpful for the court to consider what powers the Roman praetor wielded — and if he lacked a certain power, the justices should be cautious before deciding that the founders intended to entrust it to federal judges.

Interestingly, based on my initial research, it appears that the Roman praetor did not have the power to grant relief to non-parties. In fact, it seems that the praetors explicitly denied that they had the authority to issue the equivalent of a national injunction. Below, I take a brief look at this evidence and explain why it matters to the administration’s appeal.

Injunctions in the Roman Empire

In ancient Rome, the closest equivalent to the modern injunction was an interdict. An interdict was an order issued by the praetor in response to an emergency request from a plaintiff. Interdicts generally “ordered a person to do something or refrain from doing something,” and were typically used before a court had finally ruled on the merits of the case. See E. Metzger, An Outline of Roman Civil Procedure, 9 Roman Legal Tradition 1, 16 (2013).

Since the Romans did not permit suits against executive officials to enjoin the enforcement of laws, D. 2.4.2, we must look at how they used interdicts in suits between private citizens (interestingly, the Romans actually did practice a form of what we call judicial review, though without a judicial power to enjoin a law’s enforcement, see Edward S. Corwin, The Higher Law Foundations of American Constitutional Law 12–14 (1955)).

Much of what we know about Roman law (including the law of interdicts) comes from “the Digest,” a collection of writings from the greatest Roman legal thinkers compiled in the sixth century at the command of the Emperor Justinian. “The Digest” is an incredible masterpiece and one of the greatest classics of the Western world. It formed the basis of European legal education for many centuries and continues to influence American law.

In Book 43, Title 8, “the Digest” discusses interdicts issued by the praetor to enforce the Roman rule “forbidding any building to be erected in a public place.” D. 43.8.1. To ask for such an interdict, a plaintiff couldn’t simply allege that the illegal building harmed the public at large. Rather, he had to argue that it “tend[ed] to the injury of a particular individual.” D. 43.8.2. The Romans defined an “injury” as “when any benefit of any description whatever, which is derived from a public place, is lost.” If a building could stand “without causing injury to anyone,” then the praetor would not issue an interdict.

What does this mean for universal injunctions? Because the praetor’s interdicts were tailored towards remedying concrete harm to a particular plaintiff, he declined to issue relief to non-parties. The praetor would grant relief “to the extent of the interest of the plaintiff” and no further (noting that for interdicts restraining defendants from stopping repairs on public highways, “judgment is rendered under [them] to the extent of the interest of the plaintiff”).

For example, the Roman jurist Ulpian wrote that “[i]f anyone has an awning over his portico, which shuts off the light from his neighbor,” the praetor would issue the following sort of injunction: “Do not place anything in the public street which may interfere with the light of Gaius Seius [emphasis added].” D. 43.8.2.

The offender remained free to keep up his awning so long as he no longer injured the particular plaintiff (in this case, “Gaius Seius”) who had sought an injunction against him. Apparently, if his awning also blocked light to other residents, they were required to bring separate claims and seek their own plaintiff-protective interdicts.

Former US Attorney General Jeff Sessions, in his March 2018 article for National Review “Nationwide Injunctions Are a Threat to Our Constitutional Order,” pointed out that, “During the New Deal controversies, courts concluded that one new tax was unconstitutional more than 1,600 times. They issued more than 1,600 injunctions — each applying only to the plaintiff in the case.”

Conclusion

The national injunction debate has generated a remarkable amount of impressive legal scholarship. However, it seems that most scholars have not yet considered the impact that Roman law might have on this question. That is unfortunate.

The framers firmly believed in the importance of learning from classical history, and so should we. And if the Roman praetor — one of the most powerful legal figures in the history of the West — apparently lacked the authority to grant universal relief, then modern-day judges should be hesitant before assuming that power. If the Supreme Court attempts to resolve the national injunction question by looking to the founders’ intent, Justinian may prove an invaluable guide.