The Temporal Prime Directive is a Federation Starfleet principle that members of Starfleet should avoid directly interfering with the timeline in instances of time travel. (TNG: "A Matter of Time")
The Romulans also had a version of the Temporal Prime Directive that prevented the RIS Bouteina to intervene against a Vo'Quv-class carrier in 2409. (RIS Bouteina: "Quantic Fissure")
There are provisions of the Temporal Prime Directive that allow for Starfleet personnel to interact with past events and correct history, though those are rarely invoked due to the inherent and extreme danger of time travel.
One of those is Provision 34-Stroke-Omega, which the Department of Temporal Investigations invoked to allow Ambassador Harold Potter, Lieutenant Commnder Hermione Granger and Klingon Defense Force Commander Kruge to go through the Guardian of Forever and correct a historical alteration related to Potter and Granger. (Harry Potter and the Fountain of Possibilities: "Right from Wrong")
External links
- Temporal Prime Directive article at Memory Alpha, the canon Star Trek wiki.
- Temporal Prime Directive article at Memory Beta, the non-canon Star Trek wiki.