This question already has an answer here:
- Who is bound to the Prime Directive? 3 answers
The Prime Directive is a Federation concept that some others do not follow (I’m thinking Romulan, Klingon, Cardassian, possibly Ferengi).
Whenever a Federation ship discovers a new pre-warp society they are prevented from establishing contact under the Prime Directive:
The Prime Directive prohibits Starfleet personnel and spacecraft from interfering in the normal development of any society
Now, that’s all fine but leaving that society open to be discovered by any of the other warp capable species out there, especially the most aggressive ones, feels like a little dodgy from the ethical point of view, since you may argue that the main spirit of the Prime Directive is void if you allow others to interfere with that development even if you don’t do it yourself.
Are there any references (in canon preferably) about whether the Federation also protects those societies from intervention in addition to just not interfering. And would a violation of that be considered an act of war?