I think it's interesting to note that it's not the 'non-interference directive' or something else descriptive, it's the PRIME directive. As in: This is law #1. Not 'don't genocide', not 'don't start wars', not 'don't murder alien babies', but instead don't interfere. I think there's a question that's been staring us in the face for almost fifty years: Why is it the PRIME directive? This is my in-universe theory (If you're thinking 'Geesh, it's just a TV show' then please understand that I know that, but that's boring): I think something terrible happened at the result of do-gooders trying to help out primitive aliens. I believe it's evidence that something happened between Enterprise and The Original Series that shook the Federation to its core and drove the creation and implementation of this, the highest law of pace. In my imagination, something just horrible happened, and I bet this would be an interesting basis for the next TV show. Basically, chronicle the years or event(s) that lead to this. I envision a society that's coming together and reaching out into the big universe with good intentions. "We're going to make things better", parts of them say. "We will be missionaries of freedom and culture and will help other worlds avoid the pitfalls that Earth, Andoria, and Ancient Vulcan went through." In the series, they'd try to help defuse religious conflicts, provide industry to improve the lives of primitives, and so on. Of course, there are so many ways things could (and often would)go wrong. Let's say they stumble across religious conflict so Federation social workers come in and demonstrate scientific method so the primitives can "properly" take stock in the role of nature versus relying on gods. Boom, both sides unite to form a militant theocracy to push the Feds off their planet and something horrible comes into being as a result. Or, primitive workers are given industrial techniques to improve their lives, but within months they realize that this frees huge numbers of people to engage in warfare against their neighbors. "We could never organize these armies before because we needed everyone in the fields" or something. "Thanks Federation!" (war were declared) Medical advances are shared, and massive overpopulation or fear of it causes bloodshed. Technology is shared and backfires in some exciting way. Perhaps the series would culminate in a multi-planet empire of conquest coming together because of the 'helpful' meddlings of the Federation and then dying off in some terrible genocide or warfare. Multiple species are killed (maybe even species from Enterprise that weirdly don't show up later because they didn't exist yet. Really? No Xindi or Denobulans in TNG?). It becomes obvious that none of it would have ever happened if the well-meaning Federation citizens/Starfleet hadn't meddled. New rules are drafted. Federation society is struck by massive amounts of guilt over what has happened in the name of their civilization. Whole species made extinct because the arrogant Federation citizens 'knew better' leads to the drafting of what will be known as the Rule Of Space for this civilization: The Prime Directive No ifs, ands, or tribble butts. This is now THE LAW because when we didn't know better, we fucked things up.