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Trump administration and lawyers for Illinois and Chicago battle over president’s deployment of National Guard

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President Donald Trump delivers remarks before signing a Presidential Memorandum in the Oval Office on Sept. 15, 2025 in Washington, DC. Trump signed a memorandum that will send members of the National Guard and federal law enforcement agencies to Memphis, Tennessee in an effort to decrease crime in the city.
(Kevin Dietsch/Getty Images)

On Monday afternoon, the Trump administration and lawyers for the state of Illinois and the city of Chicago filed additional briefs in response to a Supreme Court order for them to discuss whether, for purposes of the federal law on which President Donald Trump relied to call up the National Guard – which allows him to do so when (among other things) he cannot “with the regular forces … execute the laws of the United States” – “the term ‘regular forces’ refers to the regular forces of the United States military, and, if so, how that interpretation affects the operation” of the law. 

The Trump administration told the Supreme Court that the law at issue refers to civilian law-enforcement officers, rather than the U.S. military. And although “the standing military was undoubtedly an available option to quash the violent resistance to federal immigration enforcement,” U.S. Solicitor General D. John Sauer argued, courts should at the very least give “extraordinary deference” to the president’s determination to send the National Guard to Chicago. 

Lawyers for the state of Illinois and the city of Chicago countered that the phrase “regular forces” “refers to the full-time, professional military.” And they urged the justices to leave in place an order by a federal judge that bars the president from deploying the National Guard to Chicago, telling the court that the Trump administration had not tried to show, and cannot show, that he could not execute federal law in Chicago with the U.S. military and therefore cannot send the National Guard instead. 

The dueling briefs were the latest – and a somewhat unusual – chapter in the battle over the Trump administration’s efforts to deploy the National Guard to Illinois. After Trump authorized the deployment of 300 National Guard members to Chicago in October, the state of Illinois and the city of Chicago challenged that decision in federal court. 

On Oct. 9, U.S. District Judge April Perry issued an order that barred the Trump administration (initially for two weeks, although she later extended that deadline) “from ordering the federalization and deployment of the National Guard of the United States within Illinois.” In an opinion accompanying her order, Perry wrote that the Trump administration had “made no attempt to rely on the regular forces” before it federalized the National Guard. Moreover, she added, the Trump administration had not argued that the president could not execute the laws with only the “regular forces.” 

The U.S. Court of Appeals for the 7th Circuit upheld Perry’s order blocking Trump from deploying the National Guard to Chicago. Sauer then came to the Supreme Court on Oct. 17, asking the justices to step in and put Perry’s order on hold. He told the justices that Perry’s order “cause[s] irreparable harm to the Executive Branch by countermanding the President’s authority as Commander in Chief, jeopardizing the lives and safety of DHS officers, and preventing the President and the Secretary of War from taking reasonable and lawful measures to protect federal personnel from the violent resistance that has persisted in the Chicago area for several months.” 

Illinois and Chicago responded that “the unnecessary deployment of military troops, untrained for local policing, will escalate tensions and undermine the ordinary law enforcement activities of state and local entities, which would need to divert resources to maintain safety and order.” Moreover, they added, the Trump administration is unlikely to win on the merits of the dispute – a key factor in determining whether to grant temporary relief. Perry concluded that the problems about which the federal government has complained “consisted entirely of opposition (indeed, sometimes violent) to a particular federal agency and the laws it is charged with enforcing,” rather than “opposition to the authority of the government as a whole.” 

In an order on Oct. 29, the court instructed the litigants to file new briefs addressing the interpretation of the federal law on which Trump relied – specifically, whether the phrase “regular forces” “refers to the regular forces of the United States military, and, if so, how that interpretation affects the operation” of the law. 

The question echoed an argument raised by Marty Lederman, a professor at the Georgetown University Law Center, in a “friend of the court” brief filed in support of Illinois and Chicago. Lederman contended that “a necessary precondition for the President’s order to deploy the National Guard to Illinois … has not been met” because the phrase “regular forces” does not include civilian law-enforcement personnel like officers from the Department of Homeland Security and Immigration and Customs Enforcement, but instead only refers to members of the U.S. military. 

In its brief on Monday, the Trump administration told the justices that interpreting the phrase “regular forces” to apply to civilian law enforcement officials was “supported by the text, structure, and history” of the law. It argued that because the president can only use the National Guard to “execute the laws” when he cannot do so using “the regular forces,” the phrase is “most naturally understood to be the civilian forces with whom the President regularly executes the relevant laws, not the standing military, which generally does not—indeed, often cannot—execute federal law.” “It is their inability to execute the laws that necessitates the use of the National Guard,” Sauer stated. Moreover, Sauer added, “there is a strong tradition in this country of favoring the use of the militia rather than the standing military to quell domestic disturbances.” 

Sauer also argued that regardless of what the phrase “regular forces” means, the Supreme Court should still pause Perry’s order because Trump rested his decision to call up the National Guard on his determination “that the regular forces of the United States are not sufficient to ensure the laws of the United States are faithfully executed” – a determination, Sauer said, that “did not specify who ‘the regular forces’ were, much less exclude the standing military from consideration.” 

And although courts do not have the power to weigh in on whether the president’s determination was proper, Sauer continued, at a minimum they “must grant extraordinary deference to the President in the exercise of his Commander-in-Chief power.” “Given the nature of the problem in Illinois,” Sauer wrote, “it was a reasonable exercise of the President’s discretion to deploy National Guardsmen, who are civilians temporarily called up to serve with deep experience in deescalating domestic disturbances … rather than the standing military, whose primary function is to win wars by deploying lethal force against foreign enemies.” 

Illinois and Chicago told the justices that when Congress enacted the law at the center of the dispute, it “understood ‘the regular forces’ to refer specifically to the full-time personnel of the United States military.” They noted that the other two scenarios in which the president can call up the National Guard – an invasion or a rebellion – “are two of the most dire exigencies the United States could face.” Allowing the president to call up the National Guard simply because he determines that civilian law enforcement officials are “greatly impeded” in executing federal laws, they said, would render the law “so broad, and thus ‘so unlike’ its two neighboring subsections, that ‘it would be implausible’ to assume Congress intended such an expansive delegation.” Moreover, they added, Congress uses the words “regular” and “forces” in other federal laws “to refer to the military or its full-time personnel and to distinguish those forces from supplementary reserve forces like the National Guard.” 

Illinois and Chicago urged the court to turn down the government’s request to pause Perry’s order because Trump “has not even attempted to execute the laws with the regular forces” – defined by them as the U.S. military – “in Illinois, let alone shown that he faces an inability to do so.” But even if the phrase “regular forces” means, as the government argues, “civilian law enforcement” officials, Illinois and Chicago continued, the Trump administration is still not entitled to a stay of Perry’s order because the Trump administration had not demonstrated “that the President is unable to execute the laws with civilian law enforcement.” 

The litigants’ reply briefs are due on Monday, Nov. 17. A decision on the government’s request to pause Perry’s order could come at any time after that. 

Cases: Trump v. Illinois

Recommended Citation: Amy Howe, Trump administration and lawyers for Illinois and Chicago battle over president’s deployment of National Guard, SCOTUSblog (Nov. 11, 2025, 9:57 AM), https://www.scotusblog.com/2025/11/trump-administration-and-lawyers-for-illinois-and-chicago-battle-over-presidents-deployment-of-the-national-guard/