How US Supreme Court blocked Trump’s bid to deploy National Guard in Chicago area

US President Donald Trump

The US Supreme Court’s refusal to allow the Trump administration to deploy National Guard troops in the Chicago area was driven in large part by a friend-of-the-court brief from Martin S Lederman, a Georgetown University law professor. The court accepted an argument that none of the parties had made, and its embrace of that reading helped produce what amounted to a stinging, if provisional, loss for the administration, the New York Times reported.

The phrase at the centre of the dispute

Lederman’s brief focused on a key phrase in the statute the administration relied on: the president may deploy the National Guard if “the president is unable with the regular forces to execute the laws of the United States.” The administration argued that “the regular forces” meant civilian law enforcement agencies, such as US Immigration and Customs Enforcement. Lederman countered that historical usage pointed in the opposite direction: “regular forces” referred to the standing US military, particularly the Army.

From weekend work to Supreme Court scrutiny

Lederman said he drafted the brief over a weekend and acknowledged he did not begin with deep background knowledge of the statute. But he identified what he described as a glaring flaw in the administration’s interpretation—one that, in his telling, the litigating parties had not focused on. The justices did. About a week after the brief was filed, the court ordered the parties to submit additional briefs addressing the question Lederman had raised.

Why the court asked for more briefing

In its order, the court asked whether “regular forces” refers to the regular forces of the United States military. The administration maintained it meant civilian law enforcement personnel. Lederman argued that when officials across the three branches discussed “the regular forces” in relation to the militia, the National Guard, or volunteer forces, they were referring to those serving in the standing military.

The majority’s tentative agreement

The court’s unsigned opinion adopted Lederman’s position in cautious terms, concluding that “regular forces” in the statute likely refers to the regular forces of the US military. On that basis, the majority said the administration had not shown that such forces could not do the job, and added that it was doubtful that protecting federal personnel and property in Illinois amounted to executing the law.

A narrow loss, and a possible incentive to escalate

Although the ruling delivered the administration its first major setback at the court in many months—after the court granted roughly 20 emergency requests asserting broad presidential power in other contexts—the loss was temporary and limited. The decision nonetheless carried practical bite, appearing to block, at least in the short term, similar National Guard deployments in Los Angeles and Portland.

Dissent and the complaint about “new” arguments

Two dissenting justices criticised the majority for entertaining an argument not presented by a party. Justice Samuel A. Alito Jr., joined by Justice Clarence Thomas, wrote that if a party passes up what the court sees as a promising argument, the justices do not normally assume the role of advocate and instead decide the questions the parties choose to present. Justice Neil M Gorsuch likewise suggested he was inclined to disregard Lederman’s argument, noting that the initial briefs assumed the president could call up and deploy the National Guard when unable to execute federal law with civilian federal law enforcement officials.

Textualism and the structure of the statute

Lederman’s reading appealed to some of the court’s conservative members because it was grounded in close attention to US Congress’s words. The law, adopted in 1903 and 1908, allows deployments for three reasons. All sides agreed the first—foreign invasion—did not apply in Illinois. The second—rebellion or danger of one—was not relied on by the majority. The court focused on the third, involving inability to execute the laws “with regular forces.”

The Insurrection Act looms, but the court did not rule on it

The ruling may shape future disputes if President Trump again tries to use the military domestically, especially as he has long floated invoking the Insurrection Act. He said in October that it could be a “way to get around” opposition to using the National Guard to support his deportation campaign, while also saying it had not yet proven necessary. The Supreme Court’s decision, however, did not address the Insurrection Act.

Kavanaugh flags a potential consequence

In a concurring opinion, Justice Brett M Kavanaugh emphasised that the court’s opinion did not reach the president’s authority under the Insurrection Act. He added that one apparent effect of the court’s reasoning could be to encourage greater reliance on the US military rather than the National Guard to protect federal personnel and property in the United States.

A related clarification on immigration stops

Kavanaugh also used his concurrence to clarify or revise language from a prior concurring opinion on immigration stops in the Los Angeles area. After earlier writing that “apparent ethnicity alone cannot furnish reasonable suspicion” but could be a relevant factor when considered with other salient factors, he added in a footnote on Tuesday that officers must not make interior immigration stops or arrests based on race or ethnicity.

Lederman’s bottom line

Lederman said he had little to add beyond what he had told the court, but underscored one point: he was pleased the court did not opine on the Insurrection Act, which he described as raising a different set of concerns.