On Tuesday reports began circulating that New Orleans officials had put the flood-ravaged city under martial law. The attorney general’s office of Louisiana quickly issued a denial. Confusion persisted, however, after White House press secretary Scott McClellan told a group of journalists on Wednesday that “martial law has been declared in Mississippi and Louisiana.” Yesterday National Guard Lt. Gen H. Steven Blum sought to set the record straight, saying, “This is not, as it has been erroneously reported, martial law.” What is martial law? And who can declare it?
Martial law occurs when the military assumes police powers because local authorities and courts aren’t functioning. Although the president usually imposes martial law, federal regulation allows for a “local commander” to do so “on the spot, if the circumstances demand immediate action.” Federal armed forces are expected to relinquish these powers as soon as the local government is once again operable. During martial law, the military may arrest and try civilians, seize private property, and institute curfews, among other emergency powers.
In practice, however, martial law has been all but barred since the late 19th century. During the Civil War, President Lincoln suspended habeas corpus and set up military courts in several states in the South and Midwest. Many at the time felt that Lincoln had superseded his authority, and in 1878 Congress passed the Posse Comitatus Act, which forbids the military from performing civilian law enforcement without congressional approval.
The Posse Comitatus Act effectively limited the president’s power to declare martial law, but it did not entirely end it. After the bombing of Pearl Harbor in 1941, the governor of Hawaii called for martial law. President Roosevelt approved the motion, and the islands remained under military authority until October of 1944.
Additionally, governors can still request that the president immediately dispatch federal troops to assist police during emergencies. This happened during two notable instances of rioting in recent history—at the 1968 Democratic Convention in Chicago and after the verdict was handed down in the Rodney King trial in Los Angeles in 1992. Neither instance constituted martial law (or violated Posse Comitatus) since federal troops were supporting and not supplanting local leaders.
During the 1987 Iran-Contra scandal, it was revealed that Oliver North had helped FEMA draft plans to overrule Posse Comitatus and impose martial rule if a major instance of civil unrest occurred. More recently, civil libertarians have worried that the military may become the de facto enforcer of law if the United States is attacked.
The Katrina relief effort includes military assistance, but it is not martial law. National Guard units are acting under the direction of governors, and federal troops are providing humanitarian relief. Neither of these violates Posse Comitatus. While martial law has not been imposed, a state of emergency has been declared in Louisiana, Mississippi, Alabama, and Florida, signaling that some civil liberties, such as the right to congregate, may be limited because of extreme conditions.
Explainer thanks Ken Pence of Vanderbilt University, Harry Scheiber of the Berkeley School of Law, and Scott Sillman of the Center on Law, Ethics and National Security at Duke Law School.