Defending Against the Military: The Posse Comitatus Act’s Exclusionary Rule

Anthony Ghiotto, Campbell University School of Law


On any given day, American military members engage in domestic law enforcement activities. Whether it’s patrolling the border, interdicting the flow of illegal drugs, monitoring internet file-sharing sites looking for potential child sex offenders, or representing the United States in federal court to enforce federal immigration laws, there has been a gradual encroachment by the military into civilian law enforcement matters. While these activities are often met with a presidential endorsement or a shrug of the shoulders by the American people, many of them are in fact a violation of federal law. The Posse Comitatus Act, passed by Congress at the end of Reconstruction, expressly prohibits the military from enforcing civilian laws. In practice, though, the Posse Comitatus Act is rarely, if ever, enforced. The judiciary is complicit in the weakening of the Posse Comitatus Act by both limiting what constitutes a violation of the Act and then refusing to apply the exclusionary rule to exclude any unlawfully obtained evidence when a violation does occur.

Nonetheless, as the military increasingly encroaches into American society, the purpose and enforcement of the Posse Comitatus Act via the exclusionary rule needs to be reexamined; otherwise, there may be little legal protection against a gradual erosion into military control. This Article makes a relatively straightforward argument: the Constitution affords each American a right to be free from military control and that the Posse Comitatus Act is an effort by Congress to protect that constitutional right. As a statute designed to safeguard a constitutional right, there must be an effective enforcement mechanism. The most appropriate enforcement mechanism available for violations of the Posse Comitatus Act is the exclusionary rule, which would allow courts to suppress evidence obtained in violation of the Posse Comitatus Act in order to deter similar encroachment in the future.

While seemingly straightforward, this argument is in fact novel. Courts and scholars have long struggled with the applicability of the exclusionary rule to the Posse Comitatus Act. Courts have been hesitant to place the Posse Comitatus Act in its true constitutional context and the growing trend is to apply the exclusionary rule only to the most egregious intentional Fourth and Fifth Amendment violations. This Article contributes to the discussion by grounding the Posse Comitatus Act in its constitutional context. By doing so, it supports the establishment of a Posse Comitatus Act exclusionary rule, built upon procedural due process, which serves to preserve the Posse Comitatus Act as an effective subconstitutional check protecting the right to be free from military control.