So that's why there's a tank at the DUI checkpoint

Rightfully so, attention after the recent mass shooting in Alabama focused on the trail of blood left by Michael McLendon, a former police officer on a rampage. But several Reuters photos taken after the incident, showing Army troops from nearby Fort Rucker patrolling the streets of Samson, Alabama, are starting to draw attention. The use of military personnel in a police role often raises concerns given their different missions and training. The practice is also, despite loosening of statutes in recent years, almost certainly illegal under federal law.

Passed in the wake of Reconstruction, when formerly rebellious regions of the country chafed under military occupation, the Posse Comitatus Act reads:

Whoever, except in cases and under circumstances expressly authorized by the Constitution or Act of Congress, willfully uses any part of the Army or the Air Force as a posse comitatus or otherwise to execute the laws shall be fined under this title or imprisoned not more than two years, or both.

The motivation for the law is clear. Military personnel are trained and equipped to wage war against an enemy. Police are trained to maintain order and keep the peace among their neighbors. The two roles don't interchange very well -- as has been amply demonstrated by the carnage resulting in recent years from increased police use of military tactics.

The Posse Comitatus law was specifically crafted to prevent the federal government from exercising direct, armed control over states and localities. As such, it doesn't apply to the National Guard, unless those state troops are federalized and placed under the command of the Army.

The Posse Comitatus Act "remains a deterrent to prevent the unauthorized deployment of troops at the local level in response to what is purely a civilian law enforcement matter."
-- Major Craig Trebilcock, a member of the Judge Advocate General’s Corps in the U.S. Army Reserve

The federal government has also moved in recent years to erode restrictions on the use of the military's vast assets for law enforcement operations. The military is now explicitly authorized to participate in drug enforcement efforts, as well as to help control immigration and collect tariffs. States can also call on federal troops to put down insurrections or help with natural disasters. The federal government can send troops of its own accord to suppress rebellions or when "major public emergencies" render state and local authorities incapable of protecting people's constitutionally guaranteed rights.

That's a lot of exceptions, but the Posse Comitatus Act remains in force. Even Major Craig Trebilcock, a member of the Judge Advocate General’s Corps in the U.S. Army Reserve, in an article otherwise dedicated to defending the domestic use of the military in anti-terrorism operations, conceded the law "remains a deterrent to prevent the unauthorized deployment of troops at the local level in response to what is purely a civilian law enforcement matter."

And the mass murder of ten people, horrible as it is, is a civilian law enforcement matter that simply doesn't rise to the level of a natural disaster or a regional insurrection.

Acknowledging the political tempest and tricky legal issues stirred up by sending troops to patrol civilian streets, the U.S. Army has released a statement acknowledging that military police were in fact dispatched to the city after the mass murder there, and that an inquiry into the use of those troops is under way.

On the Tenth of March, after a report of the apparent mass murder in Samson, 22 military police soldiers from Fort Rucker, along with the Fort Rucker Provost Martial, were sent to the city of Samson.

The purpose for sending the military police, the authority for doing so, and what duties they performed, is the subject of an ongoing commander's inquiry, directed by the commanding general of the U.S. Army Training and Doctrine Command, General Martin Dempsey.

In addition to determining the facts, this inquiry will also consider whether law, regulation and policy were followed. Until those facts are determined, it would be inappropriate to speculate or comment further.

In the aftermath of this horrific crime spree, the military community of Fort Rucker joins the greater Alabama Wiregrass community in its grief and concern for the victims and their families.

Well, an inquiry is a nice start -- if it goes anywhere.

The fact remains that there is a law restricting the use of military personnel in a law-enforcement capacity, and that law is based in sound reasoning. Troops trained and equipped for combat are a less than ideal choice for filling the roles of civilian police. If it turns out that the Army did, indeed, patrol the streets of Samson, Alabama, we should be concerned about the government's willingness to stretch or exceed the law to put troops where they don't belong.