In praise of puzzle-solving

Trump v. Illinois as a victory for textualism

On December 23, 2025, in Trump v. Illinois, the Supreme Court denied the federal government’s request to stay a lower-court order that prevented the President from deploying the National Guard in Chicago. The Court preliminarily concluded that the statutory prerequisite for deploying the National Guard—that the President be “unable with the regular forces to execute the laws of the United States”—was not satisfied.

The Supreme Court’s reasoning was formalistic and sterile. Rather than grapple with the practical and philosophical implications of the President’s use of the National Guard for law enforcement purposes, the Court relied on the literal meaning of English words and the wooden application of canons of construction. In short, Trump v. Illinois was statutory interpretation at its finest.

The 117-year streak ends

On October 4, 2025, President Trump called hundreds of National Guardsmen into active service to assist ICE’s enforcement efforts in Chicago. Illinois and Chicago sued.

I do not need to tell you that there were factual disagreements over what ICE was doing, what protesters were doing, and whether the National Guard was really needed. But the case ultimately boiled down to a question of law: was the President authorized by statute to deploy the National Guard?

The statute at issue, 10 U.S.C. § 12406, says this:

Whenever—

(1) the United States, or any of the Commonwealths or possessions, is invaded or is in danger of invasion by a foreign nation;

(2) there is a rebellion or danger of a rebellion against the authority of the Government of the United States; or

(3) the President is unable with the regular forces to execute the laws of the United States;

the President may call into Federal service members and units of the National Guard of any State in such numbers as he considers necessary to repel the invasion, suppress the rebellion, or execute those laws.

As you might guess from the admirably spare prose, this law is old. It dates back to a 1908 amendment to the Militia Act of 1903, otherwise known as the Dick Act. For 117 years, our nation has had the good fortune of being spared the circumstances that would bring this language before the Supreme Court. The reprieve has ended.

In calling the National Guard, the President relied on Subsection 3. He determined that “violent groups” have sought to “impede the deportation and removal of criminal aliens through violent demonstrations, intimidation, and sabotage of Federal operations,” and, hence, “the regular forces of the United States are not sufficient to ensure the laws of the United States are faithfully executed, including in Chicago.”

The plaintiffs, needless to say, didn’t agree. In their view, the President wasn’t “unable with the regular forces to execute the laws of the United States,” so the statutory prerequisite for calling the National Guard wasn’t satisfied. After a federal district court in Chicago agreed with the plaintiffs, and the Seventh Circuit denied a stay, the case reached the Supreme Court.

6-0-3

To decide whether the President is “unable with the regular forces to execute the laws of the United States,” you need to know what “the regular forces” are.

The government argued that “the regular forces” meant civilian law enforcement. So, according to the government, because ICE and Federal Protective Service—i.e., “the regular forces”—were unable to enforce the law on their own, the President could deploy the National Guard. The district court, however, held that “the regular forces” referred to the military, not civilian law enforcement.

Oddly, both in the court of appeals and the Supreme Court, the plaintiffs didn’t push this point; they instead argued that even if “the regular forces” referred to civilian law enforcement, they should win anyway. Why would the plaintiffs decline to advance an argument on which they had prevailed in the district court? Well, I don’t know, but if I had to guess, they were worried that if they won on this ground, the President would say “OK, fine, then I’ll send the military into Chicago,” which would be even worse from their perspective than sending the National Guard.

But the Supreme Court evidently read the district court’s decision as well as an amicus brief by Professor Lederman advancing the regular-forces-equals-military theory, and so it solicited supplemental briefing on this issue.

The supplemental briefs rolled in, and the issue turned out not to be close.

Overwhelming evidence supports the district court’s and Professor Lederman’s view that “the regular forces” means the full-time military. “Forces” refers to the military; “regular” refers to the full-time military, as opposed to the reserves. Here is a sampling of the evidence:

• Contemporary dictionaries defined “forces” and “regular forces” in exactly this way. For instance, a 1901 treatise on public international law says this: “Regular forces. — While a declaration of war in the usual form calls upon all citizens to proceed to hostilities against the enemy, in practice this duty is limited to those persons who are impressed with military character by the national authority, to such, in short, as constitute the regular army and navy.”

• Contemporary judicial decisions used “regular forces” in exactly this way. See McClaughry v. Deming, 186 U.S. 49, 56 (1902) (noting that the Founders recognized a “substantial difference between the regular forces and the militia”).

• In 1901, shortly before the Dick Act was enacted, President Roosevelt stated in his First Annual Message to Congress: “The organization and armament of the National Guard of the several States . . . should be made identical with those provided for the regular forces.” In context it is obvious that “regular forces” refers to the military. The Dick Act was enacted in direct response to the President’s advocacy: it provided that “the militia, when called into the actual service of the United States, shall be subject to the same Rules and Articles of War as the regular troops of the United States.” (In its initial form, the Dick Act used the phrase “other forces,” but this was amended to “regular forces” in 1908.)

• Even today, Congress uses the word “regular” the same way. For instance, 10 U.S.C. § 101(b)(12) recites: “The term regular, with respect to an enlistment, appointment, grade, or office, means enlistment, appointment, grade of office in a regular component of an armed force.” Congress distinguishes the “regular” forces from the “reserves.” See, e.g., 10 U.S.C. § 7062(c)(1) (distinguishing “Regular Army” from “Army National Guard” and “Army Reserve”).

In response, the government didn’t really dispute that the ordinary meaning of “the regular forces” in 1908 referred to the military. Indeed, the government’s reply brief included this rather striking acknowledgment: “Respondents and their amici show that, in other contexts, ‘the regular forces’ (and cognate terms) can, and often do, refer to the standing military, exhaustively citing various dictionaries, speeches, reports, statutes, legislative history, and judicial decisions.”

Instead, the government offered an assortment of purportedly “contextual” theories for why the Court should depart from the text. For instance, it theorized that in 1903, Congress adhered to the “traditional view that the militia rather than a standing army was the preferred means to address domestic violence.” And, according to the government, the regular-forces-equals-military interpretation was “counterintuitive” because it would require departing from that “traditional view”: “Neither respondents nor their amici identify any clear evidence supporting their counterintuitive position that, having revitalized the National Guard, the Dick Act nevertheless newly subordinated it to the standing military—let alone only for execution of the laws, not for invasions and rebellions.”

Laws are supposed to mean what they say, so this argument does not work. Indeed, when I read the supplemental briefing, I thought the issue was so lopsided that the Supreme Court would rule 9-0 against the Administration on it. It ended up being 6-0, with three Justices declining to opine. Close enough.

The three dissenting Justices argued that the Supreme Court shouldn’t have considered whether “regular forces” means “military” because the plaintiffs waived that argument. Respectfully, I disagree. The district court interpreted “regular forces” to mean the military. Lower-court decisions are entitled to respect, and the Supreme Court doesn’t reverse them unless they’re wrong. That’s why, when a party confesses error in a lower-court ruling, the Supreme Court frequently appoints an amicus to defend the lower court’s decision. I realize that the government was merely seeking a stay here, but the Court doesn’t grant stays unless there’s a likelihood that the applicant will prevail on the merits, and the government won’t prevail on the merits unless the district court’s interpretation is actually wrong.

Also, litigants aren’t entitled to stipulate as to what the law means. It’s common for litigants—particularly repeat players, such as governmental litigants—to agree, for their own convenience, that a law carries a particular meaning. But courts are never bound by those stipulations. The law means what it means, not what the parties might want it to mean. And here, the meaning of “regular forces” is painfully clear.

The dissenting Justices also argued that there was insufficient process to make a reasoned decision—“scant briefing and no oral argument.” I’m all in favor of process, but that’s not a basis to grant a stay. The Supreme Court is fond of saying that a “stay is not a matter of right,” so I have no problem with denying a stay when the briefing is inadequate. Indeed, Justice Kavanaugh’s approach in Trump v. Illinois—ruling that “regular forces” means the military, denying the stay application because the President’s order rested on the assumption that “regular forces” included civilians, and declining to address additional issues because they are complex and inadequately briefed—strikes me as a completely reasonable way of resolving this application. But the Court shouldn’t grant a stay because there was purportedly insufficient process to confirm that a lower-court decision was correct.

Babysitter Law

We’ve determined that “the regular forces” means the military. What are the implications of that?

The statute says that the President may call out the National Guard when he “is unable with the regular forces to execute the laws of the United States.”

The plaintiffs argued that “unable” means actually, physically, unable. So if the military tries to “execute the laws of the United States,” but it is overwhelmed by Antifa rioters and requires backup, the President can call out the National Guard. Here, according to the plaintiffs, the military isn’t being overwhelmed by rioters, so the President can’t call out the National Guard.

Indeed, the President hasn’t even tried to use the military to suppress the rioters. There’s a good reason for that: in 1878, Congress passed a famous law known as the Posse Comitatus Act, which (to first approximation) bans the military from being used to “execute the laws,” “except in cases and under circumstances expressly authorized by the Constitution or Act of Congress.”

There are a bunch of situations in which the President is expressly authorized to use the military for law enforcement purposes. The most famous is the scary Insurrection Act, which I sincerely hope that I will never have to Substack about. There are also approximately 25 other statutes authorizing the use of the military for law enforcement purposes, for crimes ranging from illegally settling Indian reservations to trafficking nuclear weapons. But the President hasn’t suggested—yet—that any statutory exception to the Posse Comitatus Act applies. So the President can’t call out the military to the streets of Chicago.

The government claims, as a result, that it’s “unable” to quell the riots with the military—after all, Congress banned it from doing so—which means it’s allowed to use the National Guard. The plaintiffs say “unable” means “actually unable.”

The Supreme Court held that the plaintiffs’ interpretation was correct, and I agree. In Biden v. Nebraska, Justice Barrett famously analogized Congress to parents giving instructions to a babysitter, and that’s as good a way to convey the point as any. Suppose parents tell a babysitter: “don’t give the child any Tylenol unless his fever exceeds 101°F. If you’re unable to break the fever with Tylenol, call us.” Suppose the babysitter calls the parents and says: “your child’s fever is 100°F. I was unable to break the fever with Tylenol, because you told me not to give him Tylenol unless his fever was 101°F, so that’s why I’m calling.” The babysitter isn’t interpreting the parents’ instructions correctly. The parents are saying that if the condition for giving Tylenol is met, and the Tylenol doesn’t work, then the babysitter should call. “Unable” means actually unable, not “I’m not doing it because you told me not to.”

Here, likewise, the Posse Comitatus Act says: “don’t use the military to enforce the law unless an exception applies.” The Dick Act says: “if you’re unable to enforce the law using the military, you can use the National Guard.” Congress is saying that if the President tries and fails to enforce the law using the military, he can use the National Guard, not that he’s “unable” to enforce the law using the military when Congress tells him not to.

We are not quite done yet. The government has one more arrow in its quiver. It claims that the Posse Comitatus Act doesn’t apply to its intended operations in Chicago at all.

Recall that the Posse Comitatus Act restricts the military from being used to “execute the laws,” “except in cases and under circumstances expressly authorized by the Constitution or Act of Congress.” The government claims that if the military was, hypothetically, deployed to the streets of Chicago, it wouldn’t be “executing the laws” (the thing that the Posse Comitatus Act forbids). Instead, the military would be doing a different thing: “protecting federal property and federal functions.” And the President has the inherent constitutional authority to ask the military to do that.

There are a lot of debatable premises in that paragraph, but the Supreme Court doesn’t grapple with them. Instead, it breaks out some sweet, sweet logic. The Posse Comitatus Act says that the President can’t use the military to “execute the laws.” 10 U.S.C. § 12406 says that the President can’t call out the National Guard unless he’s “unable with the regular forces to execute the laws.” Statutory-interpretation hornbooks teach that “execute the laws” must mean the same thing in both places. So if the thing the President claims he’s allowed to do—use the military to protect “federal property and federal functions”—isn’t “executing the law” for purposes of the Posse Comitatus Act, it also isn’t “executing the law” for purposes of 10 U.S.C. § 12406. Which means that the President doesn’t have a theory for how he’s allowed to even try to “execute the law” for purposes of 10 U.S.C. § 12406, which means that he isn’t unable to do so. Got that? You see, this is why they make lawyers take the LSAT.

In praise of puzzle-solving

You might find this reasoning dissatisfying.

At every step, this analysis treats the interpretation of 10 U.S.C. § 12406 as a kind of linguistic puzzle to be solved. The first step addresses how the words “regular forces” would have been understood in 1908. The second step focuses on how people communicate with their babysitters. The third step starts with an old-school statutory interpretation canon and adds some nifty deductive reasoning.

This analysis is so … limited. There is nothing about the policy merits of using the military for domestic law enforcement, the policy merits of using the regular military versus using the National Guard, or the reason we even have a National Guard. There is a little bit of history—you have to read some historical documents to understand what the words “regular forces” meant in 1908—but the historical analysis focuses on a single obscure tree and ignores the forest. There is no discussion of the broader purpose of the Dick Act, the history of state militias at the Founding and thereafter, or the interplay between state militias and the standing military. Nor is there anything about the situation on the ground in Chicago. You would have no idea, from this discussion, that the case has something to do with the use of military force to assist ICE. Can you really interpret this statute correctly without achieving a deeper understanding of these issues?

Yes.

In my view, treating 10 U.S.C. § 12406 as a logic puzzle is the correct way to resolve this case. Given the Court’s terse reasoning, one cannot be certain that it actually resolved the stay application on that ground. But that’s how I think a court should approach the issue. The court should blind itself to the nuanced and delicate and sophisticated historical and policy questions at stake and should instead stare at the English words on the page, accompanied by some limited, targeted historical research into what those words meant when they were written, until the right answer pops out.

I support this approach because it is consistent with textualism, the mode of interpretation that I favor. Textualism prescribes both a goal—interpret statutes according to their ordinary meaning at the time of enactment—and a means of achieving that goal—consider only those materials that illuminate the meaning of the text and ignore the rest. Textualism differs from other interpretive philosophies, which posit that courts should interpret statutes based on considerations such as perceived legislative purpose and predicted practical outcomes, and which by necessity require consideration of a more eclectic body of evidence. I will spare you an apologetic for textualism and instead highlight a few ways in which Trump v. Illinois shows textualism’s benefits.

First, cases—particularly highly politicized cases like this one—should be decided based on neutral principles. And the textualist principles that decide this case—like “interpret words according to their ordinary meaning at the time of their enactment” and “if the same phrase appears in two related provisions, the phrase should be construed to mean the same thing in both provisions”—are neutral.

I suppose an alternative methodology, like “interpret the statute by balancing the text with history, policy, and one’s intuitions about what makes sense” reflects a kind of neutral principle too. But that methodology is so indeterminate that it might as well not be a principle at all. Neutral principles are useful when they constrain the judge to vote in a manner that’s different from how the judge might personally prefer the case to come out.

I would prefer to avoid a dystopia in which every politically controversial case, regardless of the legal arguments, turns on personal political preferences of the judges deciding the case. And if the methodology for interpreting statutes is “balance text, history, purpose, and intuition,” then that dystopia awaits. On the other hand, if judges apply the methodology of “just try to figure out what the words mean and block out all other thoughts,” then perhaps there is some hope of avoiding that outcome.

This case illustrates the point. Suppose a judge applies the “balance text, history, purpose, and intuition” methodology. The judge might start by figuring out what the phrase “regular forces” meant in 1908. But then the judge will consider additional factors, including things like, “does it intuitively make sense that the President should have to call out the military before deploying the National Guard?” Once “intuition” enters the picture, political conservatives will think it’s intuitive that the National Guard should be assisting ICE in Chicago and political progressives will think it’s intuitive that it shouldn’t. And then at the final step, the judge has to balance all of these factors according to some ill-defined, subjective standard—an incubator for motivated reasoning. The inevitable outcome is that the judge’s legal conclusion will align with the judge’s political preference. By contrast, if the judge merely tries to figure out what “regular forces” meant in 1908 and ignores everything else, the judicial mind will have no opportunity to wander to the judge’s personal reactions to the images from Chicago he sees on TV.

Even better, this more constrained methodology allows us to achieve the dream of producing objectively correct answers to difficult legal questions. Maybe not objectively correct in the sense of 1+1=2. But from my perspective, if you focus on what the words meant in 1908 and ignore everything else, the evidence in favor of the “regular forces = military” interpretation is so strong that it’s fair to call it objectively correct. The other two issues—whether “unable” means “physically unable” and whether “executing the laws” means the same thing in the Posse Comitatus Act and the Militia Act—are closer. But when I stare at the words on the page and repeat them in my head, I’m convinced that the majority’s interpretation is just true—more convinced than I could be, anyway, if I had to start philosophizing about the reasons we have the National Guard or what would be best for Chicago.

Another core feature of textualism is that courts consider only a limited body of materials. If the court’s sole goal is to figure out what the words on the page mean, then any information that does not advance that goal is an irrelevant distraction. That is why, for example, textualist judges eschew reliance on legislative history.

Limiting the body of relevant evidence has the virtue of ensuring that judges focus on what they are good at. Judges are experts at applying Latin canons of construction and examining obscure legal texts from 1901. But they are not experts at everything.

Again, look at this case. The plaintiffs argue that there is a longstanding national tradition of “governors calling forth their own militia and, if needed, requesting assistance from the federal government and other States,” with an “established presidential practice of using the military, rather than the militia, when federal interference was warranted.” The government argues that “the Framers and early Congresses treated the militia as the first line of defense to quell domestic obstructions of civil law enforcement, while viewing a standing army as the feared last resort,” and Congress carried forward that tradition in the Dick Act. Both parties attempt to draw inferences from President Washington’s actions during the Whiskey Rebellion of 1794.

Is it really possible that a generalist court can master the relevant historical evidence to a sufficient extent to resolve this dispute accurately, particularly on the tight timeline of a stay application? Like 94% of middle-aged men, I personally enjoy reading about military history, yet I knew nothing about the historical circumstances underlying the Dick Act’s enactment until I read the briefs in this case. And judges misguided enough to have other hobbies might know even less. It is not clear that whatever historical knowledge judges acquire from this process will bear any particular relationship to reality. If you ignore the Whiskey Rebellion and focus on dreaming up babysitter hypotheticals, this problem does not arise.

I don’t want to overstate the point. One cannot resolve all interpretive disputes merely by staring at words and dictionaries. In some cases, history or policy or practicality will inevitably, perhaps desirably, drive the outcome. Every case is different.

But sometimes, staring at words and dictionaries actually works.

Happy New Year!