Section 31 - Infiltrator Cruiser
In the Star Trek fictional universe, Section 31 is the name of an unofficial intelligence and defense organization. It is presented as a special security operation, manned by United Federation of Planets citizens, that is not subject to the normal constraints of Starfleet ethical protocols.[1] The organization appears, or is mentioned, across eight episodes of Star Trek: Enterprise and Star Trek: Deep Space Nine. Within Star Trek, Section 31 exists outside Starfleet Intelligence's influence and deals with threats to Earth's and, later, the Federation's security.[2] Its operating authority stems from a provision of the Starfleet charter — Article 14, Section 31, from which its name is derived — that makes allowances for "bending the rules" during times of extraordinary threats.[3]
Section 31 is comparable to other secret police organizations in the Star Trek universe, such as the Romulan Tal Shiar and the Cardassian Obsidian Order. Unlike those organizations, Section 31 does not exist to enforce government policy or punish traitors, but rather to defend against external threats. Also, unlike the Tal Shiar and Obsidian Order, both of whom are greatly feared within their populaces, most people in the Star Trek universe have never heard of Section 31 and will never encounter it.