In August 2025, following comments from President Donald Trump that his administration needed to “federalize” the District of Columbia and “run it the way it’s supposed to be run,” the administration directed over 2,000 National Guard members from multiple states and the District of Columbia to conduct law enforcement activities in the District, including detaining people and performing armed patrols. The District went to court to challenge this use of the National Guard.

In October 2025, the Constitutional Accountability Center filed an amicus brief in support of the District, opposing the Trump administration’s motion to dismiss the case. Our brief addressed two points.

First, the Trump administration has no authority to use troops from the D.C. National Guard to create its own police force. Presidents lack inherent constitutional power to deploy the National Guard in this way, and Congress has not passed any laws that authorize the administration’s conduct either. The only law that the administration has identified to justify its actions is a section of the D.C. Code that concerns “drills and parades.” Under this provision, the Guard’s commanding general may order troops to perform “drills, inspections, parades, escort, or other duties” (emphasis added). The administration claimed that this reference to “other duties” empowers it to establish an auxiliary police force with National Guard troops. But as we demonstrated, the context surrounding these two words, along with basic principles of statutory interpretation, makes clear that “other duties” refers to other training and ceremonial duties like the ones listed, not to coercive law enforcement powers.

Second, our brief showed that the administration also lacks authority to bring National Guard troops into Washington, D.C., from outside the District to perform law enforcement functions. Here, too, the administration’s argument rested on misreading a few words in a single portion of a statute while ignoring everything surrounding those words. Specifically, the administration insisted that a section of federal law titled “drills and field exercises” allows presidents to use National Guard troops for any type of mission the President might order, anywhere, so long as a governor somewhere lends troops to the effort. The administration based this staggering claim on the law’s vague reference to troops performing “operations or missions” requested by the President. If accepted, this argument would have allowed presidents to order troops into any state, for any type of mission, with these troops remaining entirely outside the disciplinary authority of the officials where they operate. This argument also would have enabled presidents to sidestep numerous laws that place limits on using military power for law enforcement.

In November 2025, the district court denied the Trump administration’s motion to dismiss the case and granted the District’s motion for a preliminary injunction, holding that the administration likely lacks statutory authority for its unprecedented use of the National Guard. Relying in part on arguments that were unique to our brief, the court determined that the D.C. Code does not authorize the administration’s deployment of the National Guard as a roving crime-fighting force in the District. In further alignment with our brief, the court concluded that federal law does not permit the President to send any state’s National Guard units into any other jurisdiction for any “operations or missions” the President might devise—recognizing that this interpretation would allow presidents to evade numerous checks on their power to use the National Guard for law enforcement.

The government appealed the district court’s order to the Court of Appeals for the D.C. Circuit and sought a stay of the district court’s order. In December 2025, CAC filed an amicus brief in opposition to the motion to stay, reiterating why the Trump administration’s actions are unlawful.