How have federal courts historically adjudicated challenges to past invocations of the Insurrection Act, and what precedents would matter in 2026 litigation?
Executive summary
Federal courts have long treated presidential invocations of the Insurrection Act as presumptively political and thus often nonjusticiable, but that deference has limits: courts have intervened where legal text, statutory compliance, Posse Comitatus constraints, or clear bad faith are implicated [1] [2]. Recent litigation and Supreme Court orders in 2025–2026 have tightened that landscape, making statutory reading, the definition of “regular forces,” and evidence of prohibited domestic-law-enforcement activity central to any 2026 challenges [3] [4] [5].
1. The old anchor: Martin v. Mott and the historical presumption of presidential exclusivity
The canonical precedent often invoked for presidential latitude is the 1827 Martin v. Mott decision, where the Court said the President’s decision to call out the militia “belongs exclusively to the President,” language that courts and commentators still cite to justify nonintervention [1] [6]; but scholars and the Brennan Center emphasize that Mott’s factual context—a militia mobilization in wartime—limits its reach and that later Supreme Court guidance carves out exceptions where the president acts in bad faith or beyond honest judgment [1].
2. Posse Comitatus and modern statutory checks: courts policing what troops actually do
Federal courts in recent years have not accepted wholesale existential claims that any military deployment is lawful; judges have scrutinized whether deployed forces performed traditional law-enforcement functions barred by the Posse Comitatus Act, with district judges finding violations when troops made arrests, conducted traffic control, or engaged in crowd control in Los Angeles and elsewhere [5], underscoring that statutory limits on military involvement remain a live judicial check [4].
3. The Supreme Court’s recent posture: narrow procedural rulings with implications for scope
The Supreme Court’s emergency handling of Trump v. Illinois and related matters has produced narrow procedural rulings that nevertheless constrain certain deployment strategies—most notably limiting federalization routes under 10 U.S.C. §12406 and signaling skepticism about invoking protective-function rationales to justify using the military to “execute the law” [3] [7]. These orders leave unresolved some Article II arguments and explicitly invite litigation focused on statutory text and whether the Insurrection Act authorizes specific protective uses of regular forces [3] [7].
4. Lower-court developments as a roadmap for 2026 litigation
District courts have already supplied concrete doctrinal hooks: Judge Charles Breyer ruled a Los Angeles deployment violated Posse Comitatus by engaging in law-enforcement activities [5], and Judge Karin Immergut rejected federalization in Oregon—decisions that together show plaintiffs can win injunctions by proving statutory misapplication or prohibited conduct, a playbook likely to be replicated in 2026 challenges where plaintiffs present factual records of military policing [5].
5. Statutory text, “regular forces,” and congressional fixes that will matter in court
Key legal battlegrounds for 2026 will be statutory interpretation questions—what the Insurrection Act’s triggers precisely cover, whether “regular forces” means active-duty military versus the National Guard, and how Posse Comitatus fits into that framework—issues the Court and scholars (including Steve Vladeck) have flagged as decisive [4] [8]. Concurrently, Congress has floated statutory revisions (S.2070) that would clarify triggers, procedural checks, and private-rights-of-action, and any enacted change or pending legislation will shape how courts analyze prudential and textual claims [9].
6. Litigation strategy and the judicial appetite in 2026: prove statutory violation or operational law-enforcement conduct
Given recent precedent and lower-court wins, successful 2026 challenges are likely to hinge less on abstract constitutional theory and more on showing that an invocation fails statutory prerequisites or that deployed forces are performing prohibited law-enforcement functions; courts have signaled willingness to step in where the record shows unconstitutional or unlawful application, or where statutory text forecloses claimed authority [1] [5] [3]. Where factual records are thin or claims rest on broad Article II assertions, historical deference from Martin v. Mott and other precedents may still pose an obstacle [1].