The Commonwealth of Puerto Rico, a territory of the United States where 3.4 million U.S. citizens reside, is suffering a humanitarian crisis following Hurricane Maria. Lt. Gen. Buchanan, the Defense Department’s primary liaison with the Federal Emergency Management Agency (FEMA), has declared that the devastation is the “worst he has ever seen.” To date, at least 16 people have died (and that number is expected to rise), and it is estimated that half the population is without drinking water. The president has correctly declared that an emergency exists in Puerto Rico, triggering important federal funding streams and related FEMA support via the Stafford Act. And the U.S. military is now coming: The U.S. Navy hospital ship Comfort and amphibious ship Wasp are sailing to Puerto Rico to assist with the recovery effort. Northern Command has recently stepped up its humanitarian assistance efforts by naming a three-star general to oversee the entire operation.

While much of the legal discussion has focused on common-sense waivers for the 1920 Jones Act that would facilitate shipment of humanitarian assistance to Puerto Rico, one of the reasons given for the initial slow response was complications stemming from the Posse Comitatus Act (PCA), which limits the role that active military personnel can play in responding in U.S. territories. But what is a “posse comitatus,” and is this a legitimate concern for the military in responding to the crisis?

While the PCA does limit the regular Army and Air Force from taking an active role in civilian law enforcement, I have previously argued its practical application requires a much more nuanced understanding. As questions arise about the PCA’s applicability in Puerto Rico in light of the U.S. military response, I frame its applicability to the evolving crisis in Puerto Rico via four questions:

(1) What does the text of the Posse Comitatus Act say?

(2) Where does the Posse Comitatus Act apply?

(3) To whom does the Posse Comitatus Act apply?

(4) To what actions does the Posse Comitatus Act apply? 

First, what does the PCA say?  This is straightforward. Enacted during the Reconstruction-era (1878) in response to the federal occupation of the American South by federal troops (not during the time of the nation’s founding—a common misunderstanding), it reads in its current form:

Whoever, except in cases and under circumstances 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 term “posse comitatus” is outdated terminology, conjuring images of the Wild West when western sheriffs commandeered military personnel to assist with law enforcement efforts on the frontier—not an uncommon occurrence at the time of the law’s passage. The key provision is the prohibition on “execut[ing] the laws,” preventing the “Title 10” (i.e. federal) Army or Air Force from taking an active role in domestic law enforcement effort. The Air Force was added in 1956, but noticeably absent in the statute is any reference to the National Guard, Navy, Coast Guard, or Marines—more on that below.

Second, where does the PCA apply? The short answer is that it does apply in Puerto Rico. Unlike previous military-led humanitarian assistance missions following natural disasters in the Caribbean (such as after the earthquake in Haiti in 2010), Puerto Rico is a U.S. territory subject to U.S. law. While the PCA does not apply extraterritorially, Puerto Rico is a U.S. territory where federal laws apply pursuant to Article IV of the Constitution and Title 48 of U.S. Code.

Third, whom does the PCA apply to? Now we are starting to enter the territory of more difficult questions. The PCA’s text explicitly applies to the active Army and Air Force. The PCA makes no mention of the “militia” (the modern National Guard), hence it does not apply to the National Guard of any service when operating pursuant to state authorities. And there is no mention of its application to the Coast Guard, Navy and Marine Corps. This is of central importance to the Puerto Rico assistance effort as the maritime services are playing an outsized role in the delivery of humanitarian assistance.

Courts have generally construed that the PCA does not apply to the Coast Guard, and jurisprudence on the statute’s applicability to the Navy and Marines have been uneven with most federal courts refusing to extend the Act’s prohibitions to the Navy or even Marines. Yet the Department of Defense (DoD) applies the PCA’s limitations on law enforcement to the Navy and Marines as a matter of regulation via a DoD directive on cooperation with civilian law enforcement officials. As Puerto Rico is an island requiring a large maritime response, this statutory v. regulation distinction should be kept in mind, as regulations are easier to waive than the law itself.

Fourth, what does the Posse Comitatus Act apply to? This is likely the most important question as courts have used various tests to determine what crosses the line from a valid military purpose to a law enforcement function. The PCA does restrict the federal Army and Air Force (not National Guard) from “executing the laws”—i.e. taking a more active role in law enforcement that has been construed to mean “regulatory, proscriptive, or compulsory in nature.” So taking an active role in law enforcement would violate the PCA absent waiver or a separate legal authority such as the president invoking his authority pursuant to the Insurrection Act. The PCA does not apply to actions furthering a military or foreign affairs function of the United States, and there are numerous actions that are authorized under Defense Support to Civilian Authorities guidance.

But any military service, whether under state or federal authority, can conduct a humanitarian assistance mission. For example, protecting federal property (such as the underlying aid) or members delivering aid is clearly authorized, and the military’s presence should facilitate aid delivery. At this time, the immediate need in Puerto Rico is humanitarian in nature to include logistical support—not law enforcement. Military support to disaster relief operations (i.e. logistics, health care, transportation) are not subject to PCA restrictions. If the security situation degraded and the military was requested to take a direct and active role in law enforcement, only then would the PCA’s prohibitions be triggered.

In sum, the National Guard is conducting the bulk of the humanitarian assistance effort in Puerto Rico, clearly not prohibited by the PCA. And the National Guard is heavily assisted by the maritime services, who fall outside the text of the law itself.  Thankfully, there is not a clear security and law enforcement need at this time. The military should continue to play a robust role in the military response to Puerto Rico. Hopefully, the assistance will alleviate the crisis in Puerto Rico, and the U.S. citizens residing there will get the help they so desperately need and deserve. And understanding when and when not to apply the PCA should ensure the military response is timely and not thwarted by any restrictions, real or perceived.

Image: U.S. Navy