What legal steps allow a U.S. president or governor to declare martial law during midterm elections?
Executive summary
A U.S. governor can, under state constitutions and statutes and historical practice, proclaim martial law within his or her state when faced with insurrection, invasion, or extreme civil disorder, subject to state law and judicial review [1] [2]. By contrast, the president has no clear constitutional or statutory power to unilaterally “declare martial law” nationwide: Congress has tightly regulated domestic military use, the Posse Comitatus line constrains federal troops in civilian law enforcement, and leading legal scholarship concludes a presidential martial‑law proclamation would likely violate those constraints and be subject to litigation [3] [2] [1].
1. What “declaring martial law” means and who has historically done it
Martial law is the temporary substitution of military authority for civilian rule in areas affected by war, rebellion, or severe civil disorder, and historically has been used by both state governors and federal authorities on limited occasions in U.S. history [4] [2]. States and territorial officials have invoked it most often: from Civil War instances to dozens of state uses between the 19th and 20th centuries, governors, mayors and military commanders have declared martial law in discrete localities [2] [5].
2. How a governor can legally impose martial law during an election period
A governor typically relies on state constitutions, emergency statutes, or explicit legislative delegations to proclaim martial law or to call out the National Guard to restore order; those declarations are constrained by state law and by federal constitutional limits, and courts have sometimes enjoined governors who overreached—such as preventing disenfranchisement—demonstrating judicial checks on state proclamations [1] [6]. Territorial statutes likewise authorize territorial governors in narrow circumstances to suspend habeas corpus or place territories under martial law until consultation with the president, showing statutory pathways at the territorial level [7] [2].
3. Why a president cannot unilaterally cancel or suspend elections by declaring martial law
The Constitution does not explicitly give the president power to declare martial law, and modern legal scholars and institutions conclude the president lacks that unilateral authority; Congress has “occupied the field” of domestic military authority through statutes and the Posse Comitatus restrictions, and Youngstown‑style separation‑of‑powers analysis would undercut a president’s effort to act contrary to those statutes [1] [3]. The Brennan Center and other legal commentators argue a presidential declaration of martial law would run into statutory prohibitions on using federal forces for civilian policing and would not survive legal challenge absent clear congressional authorization [2] [3].
4. Federal options short of a sweeping “martial law” proclamation
If the federal government seeks to use troops or federal forces in a state during unrest, the typical legal route is statutory: statutes like the Insurrection Act permit limited federal deployment to suppress insurrection or enforce federal law when states are unwilling or unable to do so, but those deployments are narrow, legally conditioned, and subject to political and judicial scrutiny [8] [3]. Declaring a national emergency can unlock certain executive powers, but even emergency statutes do not give the president carte blanche to suspend elections or substitute military rule for civilian courts without congressional or judicial acquiescence [9] [3].
5. Practical and legal constraints, plus alternative views
Practically, attempts to use military power to alter or stop elections would face statutory barriers, Posse Comitatus constraints, political backlash, and rapid litigation; historical cases show courts have both deferred and checked executive and gubernatorial uses of martial law depending on context, and scholars disagree about edge cases but largely reject the view that a president can lawfully cancel elections by fiat [6] [7] [3]. Some commentators and advocates warn that invoking emergency authorities could be abused to undermine democratic processes, while others stress that existing laws and judicial review are designed to prevent precisely that outcome [9] [3].