|Universe||Star Trek universe|
|Founded||Established in Starfleet charter|
|Key people||Agent Harris (2150s)
Agent Luther Sloan (2370s)
|Purpose||Defend the United Federation of Planets by any means necessary|
|Technologies||Classified, United Federation of Planets' technologies|
|Affiliations||United Earth (superseded)
United Federation of Planets
In the Star Trek fictional universe, Section 31 is an autonomous intelligence and defense organization. It is presented as a special security operation, manned by Federation citizens, that is not subject to the normal constraints of Starfleet ethical protocols. The organization appears, or is mentioned, across nine episodes of Star Trek: Deep Space Nine and Star Trek: Enterprise as well as the 2013 movie Star Trek Into Darkness.
In the Star Trek storylines, Section 31 exists outside Starfleet Intelligence's influence and deals with threats to Earth's and, later, the Federation's security. 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.
Unlike other secret police organizations in the Star Trek universe, such as the Romulan Tal Shiar and the Cardassian Obsidian Order, Section 31 is not an actual branch of government. Accountable to no one, Section 31 focuses on external threats, and pursues those it identifies by whatever means it sees fit.
Little of Section 31's history has been revealed on-screen. Most references to the organization appear in episodes of Deep Space Nine, although Section 31 also appears in Star Trek: Enterprise. Several works of Star Trek spin-off fiction expand on Section 31's operations; Pocket Books published a four-part series profiling connections between Section 31's operations and the missions of James T. Kirk, Jean-Luc Picard, and the crews of Deep Space Nine and the USS Voyager. These novels explicitly link Section 31 to Fleet Admiral Cartwright's actions in Star Trek VI: The Undiscovered Country and Vice Admiral Matthew Dougherty's actions in Star Trek: Insurrection. Section 31 is also heavily featured in the Star Trek: Enterprise novel The Good That Men Do, in which Trip Tucker joins the organization after his supposed "death".
The film Star Trek Into Darkness features an alternate universe version of Section 31, which is run by Starfleet Supreme Commander Admiral Marcus. As with the original continuity, Section 31 is a secret branch of Starfleet created to protect the Federation from external threats by developing weapons. Marcus' involvement in the organization includes awakening the cryogenically frozen Khan Noonian Singh, whose genetically altered intellect allowed Marcus to develop new weaponry, including the U.S.S. Vengeance, a state-of-the-art warship. However, Marcus' plans and role in Section 31 were eventually halted by the unlikely alliance of Khan and the crew of the USS Enterprise.
Controversial topics 
The implications of Section 31 have been described as "troubling" and its goals and methods "deeply questionable". Its methods include brainwashing, torture, assassinations and, as revealed by the end of the Deep Space Nine TV series, genocide, the crime that is most opposed by the Federation. The genocide involves the creation, by Section 31, of a virus designed to kill a single species, the Founders, with the aim of destroying the Dominion. Section 31 deliberately infected Odo with this virus, knowing he would spread it to other founders.
Throughout the series, several Deep Space Nine officers, including Julian Bashir, infiltrate Section 31. One of their aims was to obtain a cure for the virus which was threatening Odo's life, however, under orders from Captain Sisko, they ultimately collude in hiding the crime. This is part of a pattern of overall loss of moral credibility by Starfleet, in comparison to that which it had in the original series and The Next Generation. The Deep Space Nine series and the film Star Trek: Insurrection both "position the Starfleet authorities in a very dubious light".
Section 31 agents include the following characters:
- Luther Sloan: Star Trek: Deep Space Nine
- Harris: Star Trek: Enterprise
- Malcolm Reed: Star Trek: Enterprise
- Admiral Alex Marcus, Thomas Harewood, John Harrison: Star Trek Into Darkness
- Novels only:
- Charles Tucker III (Star Trek: Enterprise; novel The Good That Men Do)
- Admiral Cartwright (Star Trek VI; novel Section 31: Cloak)
- Admiral Dougherty (Star Trek: Insurrection; novel Section 31: Abyss)
- Commander Cortin Zweller (Star Trek: The Next Generation; novel Section 31: Rogue)
- Ambassador Aubin Tabor (Star Trek: The Next Generation; novel Section 31: Rogue)
- Ensign Roberta Luke (Star Trek: Voyager; novel Section 31: Shadow)
- Video games only:
- Franklin Drake: (Star Trek Online)
- Star Trek: Enterprise
- Although produced later, these episodes come chronologically before the below Deep Space Nine episodes.
- Star Trek: Deep Space Nine
- "Inter Arma Enim Silent Leges"
- "When It Rains..."
- "Tacking Into the Wind"
- "Extreme Measures"
- Star Trek movies
- Star Trek Into Darkness (mentioned)
- Star Trek novels
- The Good That Men Do (Enterprise novel)
- Kobayashi Maru (Enterprise novel)
- The Romulan War: Beneath the Raptor's Wing (Enterprise novel)
- Star Trek: Section 31: Rogue by Michael A. Martin and Andy Mangels (June 2001)
- Star Trek: Section 31: Shadow by Dean Wesley Smith and Kristine Kathryn Rusch (June 2001)
- Star Trek: Section 31: Cloak by S.D. Perry (July 2001)
- Star Trek: Section 31: Abyss by David Weddle and Jeffrey Lang (July 2001)
- Typhon Pact: Plagues of Night (The Next Generation) by David R. George (July 2012)
- Star Trek comics
- Star Trek video games
Further reading 
- Jeffrey T. Richelson (July 2003). "The IPCRESS File: The Great Game in Film and Fiction, 1953–2002". International Journal of Intelligence and CounterIntelligence 16 (3): 462–498. doi:10.1080/713830443.