Quis custodiet ipsos custodes?


Quis custodiet ipsos custodes? is a Latin phrase found in the work of the Roman poet Juvenal from his Satires. It is literally translated as "Who will guard the guards themselves?", though it is also known by variant translations, such as "Who watches the watchers?" and "Who will watch the watchmen?".
The original context deals with the problem of ensuring marital fidelity, though the phrase is now commonly used more generally to refer to the problem of controlling the actions of persons in positions of power, an issue discussed by Plato in the Republic. It is not clear whether the phrase was written by Juvenal, or whether the passage in which it appears was interpolated into his works.

Original context

The phrase, as it is normally quoted in Latin, comes from the Satires of Juvenal, the 1st–2nd century Roman satirist. Although in its modern usage the phrase has universal, timeless applications to concepts such as tyrannical governments, uncontrollably oppressive dictatorships, and police or judicial corruption and overreach, in context within Juvenal's poem it refers to the impossibility of enforcing moral behaviour on women when the enforcers are corruptible :
Modern editors regard these three lines as an interpolation inserted into the text. In 1899 an undergraduate student at Oxford, E. O. Winstedt, discovered a manuscript containing 34 lines which some believe to have been omitted from other texts of Juvenal's poem. The debate on this manuscript is ongoing, but even if the verses are not by Juvenal, it is likely that it preserves the original context of the phrase. If so, the original context is as follows :

In popular culture

The question "Who watches the watchmen?" often partially appears as graffiti scrawled in the background of Alan Moore and Dave Gibbons' graphic novel Watchmen, but the phrase is never seen in its entirety. Moore stated in an interview that the title of the series related directly to this question, although at the time of the interview Moore did not know where the sentence originated.
Science fiction author Robert A. Heinlein chose the original Latin phrase as the motto of the Solar Patrol, as depicted in his 1948 novel Space Cadet.
The internet comedy group LoadingReadyRun made a video parodying the question of 'Who watches the Watchmen?', proposing that the Watchmen watch the city, the 'Neighbourhood Watchmen Watching Organisation' watch the Watchmen, the 'Watching The Neighbourhood Watchmen Watching Organisation Organisation' watch the Neighbourhood Watchmen Watching Organisation, and Geoff watches the 'Watching The Neighbourhood Watchmen Watching Organisation Organisation'. An unnamed person is seen to be watching Geoff.
The independent film The Guards Themselves by Kyle C. Sullivan and Ian Conn takes its title from this phrase. It tells the tale of a group of so-called anarchists who appear to be villains endeavoring to overthrow the government and who are thwarted repeatedly by supposedly heroic vigilantes. However, the government in their city is corrupted by an actually villainous group of five oligarchs, and the vigilantes are primarily out for publicity; it is the anarchists who are the true guards of their city.
An episode of Inspector Morse references this quote. Whilst speaking with the prison governess Hilary Stephens in an Oxford college, Morse encounters his former college chaplain. Upon finding out that the head of a prison is off prison premises he asks "quis custodiet ipsos custodes?" Morse finds it amusing since the chaplain says this every time the two meet, only this time it is "remotely apposite".
An episode of the animated series The Simpsons refers to this philosophical question. In episode 1F09, "Homer the Vigilante", when Homer is talking about having abused his vigilante powers, his elder daughter Lisa asks, "If you're the police, who will police the police?" Homer responds, "I don't know. Coast Guard?"
It appears frequently in Terry Pratchett's Discworld novels, usually heard from Sir Samuel Vimes, commander of the City Watch. He answers it in Thud!, though very briefly, with the line "I do". When asked who watches over him, he follows it up with "I do, too". It also appears in Feet of Clay and I Shall Wear Midnight. It first appears in Guards! Guards! from a citizen, also addressed to Vimes, as: "Quis custodiet custard?"
"Who Watches the Watchers" is an episode of ' involving a group of anthropologists who are observing a primitive culture from a concealed location, but are revealed following an accident.
In Dan Brown's novel Digital Fortress, the phrase appears engraved in a ring owned by Ensei Tankado, a former NSA employee who disapproved of the NSA's intrusion into the people's private lives. The phrase is aimed at the NSA who check for any information on emails sent over the web that endanger national security. The phrase asks who will keep the NSA in check, as they do others.
In Did I Ever Tell You How Lucky You Are? by Dr. Seuss, the entire town of Hawtch-Hawtch is employed as watchers watching over other watchers leading to the first watcher who is watching the "lazy town bee" so it will work harder. Since the bee wasn't working harder, it was assumed the bee-watcher wasn't watching hard enough and needed to be watched.
In the video game ', the seventh Terminal's description is "Who monitors the Monitor?", and details 343 Guilty Spark's frustration with loneliness. The replacement of "watchmen" with "Monitor" is a reference to Guilty Spark's position of Monitor of Installation 04.
During an episode of Justice League Unlimited, Batman says the phrase to Green Arrow after Arrow talked Superman and the other founding members out of disbanding the League. Green Arrow translates the Latin to "Who guards the guardians". Superman's reason for disbanding the League was that the League were guilty of arrogance, and have alienated the people they were trying to protect. Green Arrow's reason not to disband is that no matter what, they are still heroes and needed greatly.
In , the phrase is handwritten on a floor support near the staircase as Batman carries a weakened Superman over his shoulder at the climax of their duel.
In the Person of Interest television series, if The Machine ever suffered a hard reset it would then ring a public phone and ask the phrase, and whoever answered the call would have administrative access for 24 hours.
In the comic book series Countdown to Final Crisis, Donna Troy asks the question "Who monitors the monitors?" in regards to the 52 monitors from parallel universes and who will keep them in line, following the events of the story.
In Letter VIII of "Meditations on the Tarot: A Journey into Christian Hermeticism", on Justice, the anonymous author includes the phrase in one of the opening epigraphs as follows: "Quis custodiat custodes? ".
In the video game The Evil Within 2, the character Julian Sykes quotes the Latin phrase to protagonist Sebastian Castellanos in reference to Sykes himself having found an escape route, with Sykes abandoning his mission by the company Mobius that hired him. Sebastian expresses confusion at the phrase when given no explanation.
In the first episode of Watchmen, the character Police Chief Judd Crawford quotes the Latin phrase to his assembled Tulsa, Oklahoma, police force to invoke Article 4, which allows the 24-hour release of deadly weapons. The police force calls back, in unison, "Nos costodimus", which means "we uphold".