The Prime Directive of the United Federation of Planets
"Insofar as we, the members of the United Federation of Planets, do recognize and respect the vital role that each and all our separate peoples have played in the building of our union, and insofar as that union is then the product of our differences as well as our commonalities, one built as much of the acknowledgment of our failing as the recognition of our potentials, we so do resolve, as a United Federation of individual Planets strong both in spirit and the desire to live free, never to lose sight of those principles which by fate or providence, have served to establish this Federation as a meeting of equals.
We shall foster within the bounds our common influence the inescapable belief that all life is possessed of the inalienable right to flourish on its own terms and its own time and place.
Therefore, we devote our energies to the establishment and fostering of such state in equal measure throughout the Known Galaxy, and dedicate our Star Fleet to the preservation and protection of that state; that state being an insular program of non-interaction and non-interference with those cultures whose development of self and whose singular right to self determination would be unduly burdened or damaged by the interaction with, or even the knowledge of, more technologically advanced races, even those whose motives and intentions are unimpeachable and altruistic, even unto the destruction of the culture by lack of action, it being none the more justifiable to crush the special essence of a new culture in the process of saving it.
We shall do all within our power to leave the development of any and all cultures to their own devices, to let them flourish or fail as their differing gifts allow, and to prevent any and all who would deprive them of this, the most basic right, from performing self-serving and selfish actions at the expense of the innocents, until such time as they, themselves, come forward, as equals, and mindful of their place within the greater whole.
We stand unified in our avowed proclamation of this as first and foremost principle, our PRIME DIRECTIVE".
Star Trek Plot Summaries - "Patterns of Force"
When the Enterprise approaches the inner planet Ecos to investigate the cessation of communication with researcher John Gill, it is attacked with a rocket carrying a nuclear weapon.
This is puzzling as well as dangerous, since neither the outer planet Zeon nor the inner planet Ecos is technologically advanced enough to possess rockets or nuclear warheads. The Enterprise retreats to maximum orbital distance and Kirk and Spock beam down (after having position-broadcasting transponders surgically implanted in the case of mishaps).
Kirk and Spock discover that a Nazi movement has swept the planet, complete with genocide of the "Zeon Pigs" residing on Ecos. They view a public newscast in which the Iron Cross second class is presented to Daras, hero of the Fatherland. Kirk and Spock are also shocked to learn that Gill appears to be the leader of the planet's Nazi movement. When they are approached and questioned by a Nazi Lieutenant, they overpower him and Spock steals his uniform. Spock then pretends that Kirk is a Zeon he has captured and nerve pinches a Gestapo commander who wishes to take charge of Kirk. This provides Kirk's uniform, and Spock compliments Kirk by telling him "You should make a very convincing Nazi".
As Kirk and Spock make their way to see the Fuhrer, they are confronted by a Nazi S.S. Major after Spock neglects to salute him. The Major becomes suspicious and Spock is exposed when he is forced to remove his helmet. Spock and Kirk are whipped in the process of being interrogated. Nazi Party Chairman Eneg interrupts the "questioning" and tells the Nazis to lock up Spock and Kirk for an hour (in contradiction to standing orders to execute prisoners after interrogation).
In prison, Kirk and Spock speak to an imprisoned Zeon (whom they have previously encountered being beaten on the streets by the Nazis) and find that the Nazi movement began several years ago (corresponding with the arrival of Gill).
They escape from prison by making a primitive laser from the rubidium crystals in their transponders using their cell's incandescent bulb as the excitation source (not quite a flash arc and ruby crystal, but close enough in a pinch). Spock hides outside the cell and then nerve pinches the guard when Kirk summons him under the pretext of wanting to talk. Kirk and Spock also allow the Zeon prisoner to tag along.
Kirk and Spock penetrate Nazi headquarters with the help of secretary Damas and Chairman Eneg. They discover that Gill is only the drugged puppet of Fuhrer Melakon after he gives a stilted speech unleashing the final assault on Zeon, McCoy is beamed down and manages to barely overcome the drug. Gill tells them that he started the Nazi movement to unify the planet (because it was the "most efficient system Earth ever knew"). With an extra hypo from Kirk, Gill manages to call back the invasion fleet and denounce Melakon as a traitor. Melakon grabs a machine gun and kills Gill, only to be shot himself. Chairman Eneg takes over and stops the killing, declaring that "it is time to live the way our Fuhrer intended." Kirk and company then return to the Enterprise in peace.