The #Insurrection #Act authorizes the president to deploy military forces inside the United States to suppress #rebellion or domestic #violence or to enforce the law in certain situations.
The statute implements Congress’s authority under the Constitution to “provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions.”
It is the primary exception to the #Posse #Comitatus #Act, under which federal military forces are generally barred from participating in civilian law enforcement activities.
Although it is often referred to as the “Insurrection Act of 1807,” the law is actually an amalgamation of different statutes enacted by Congress between 1792 and 1871.
Today, these provisions occupy Sections 251 through 255 in Title 10 of the United States Code.
Under normal circumstances, the Posse Comitatus Act forbids the U.S. military
— including federal armed forces and National Guard troops who have been called into federal service
— from taking part in civilian law enforcement.
This prohibition reflects an American tradition that views military interference in civilian government as being inherently dangerous to liberty.
Invoking the Insurrection Act temporarily suspends this rule and allows the president to deploy the military to assist civilian authorities with law enforcement.
That might involve soldiers doing anything from enforcing a federal court order to suppressing an uprising against the government.
Of course, not every domestic use of the military involves law enforcement activity.
Other laws, such as the #Stafford #Act, allow the military to be used to respond to natural disasters, public health crises, and other similar events
without waiving the restrictions of the Posse Comitatus Act.
In theory, the Insurrection Act should be used only in a crisis that is truly beyond the capacity of civilian authorities to manage.
However, the Insurrection Act fails to adequately define or limit when it may be used and instead gives the president significant power to decide when and where to deploy U.S. military forces domestically.
Troops can be deployed under three sections of the Insurrection Act.
Each of these sections is designed for a different set of situations.
Section 251 allows the president to deploy troops if a state’s legislature
(or governor if the legislature is unavailable)
requests federal aid to suppress an insurrection in that state.
This provision is the oldest part of the law, and the one that has most often been invoked.
While Section 251 requires state consent,
Sections 252 and 253 allow the president to deploy troops without a request from the affected state,
even against the state’s wishes.
Section 252 permits deployment in order to
“enforce the laws” of the United States or to
“suppress rebellion” against the U.S. government whenever
“unlawful obstructions, combinations, or assemblages, or rebellion”
make it “impracticable” to enforce federal law in that state by the
“ordinary course of judicial proceedings.”
Section 253 has two parts.
The first allows the president to use the military in a state to suppress
“any insurrection, domestic violence, unlawful combination, or conspiracy”
that “so hinders the execution of the laws”
that any portion of the state’s inhabitants are deprived of a constitutional right
and state authorities are unable or unwilling to protect that right.
Presidents Dwight D. Eisenhower and John F. Kennedy relied on this provision to deploy troops to desegregate schools in the South after the Supreme Court’s landmark decision in Brown v. Board of Education.
The second part of Section 253 permits the president to deploy troops to suppress
“any insurrection, domestic violence, unlawful combination, or conspiracy”
in a state that
“opposes or obstructs the execution of the laws of the United States
or impedes the course of justice under those laws.”
https://www.brennancenter.org/our-work/research-reports/insurrection-act-explained
