Of all the nefarious villains found within the Star Trek universe, none are so terrifying or prominent as the Borg. This cybernetic-infused race of stolen bodies and minds have made appearances in the majority of the shows ever since their introduction in the very first episode of The Next Generation, and have destroyed many cultures and lives over their existence. While they have no doubt caused a lot of pain and suffering, their presence could be seen as a necessary evil, and the consequences of removing them from the timeline could have disastrous effects.
This is, of course, a fairly hypothetical question: exploring what different paths the Federation and the heroes of the shows would have taken if the Borg were dealt with before they became a threat to all life in the Galaxy. The writers aren't afraid to explore the concept of time travel, with episodes such as “Year of Hell” and “The City on the Edge of Forever.” But as these episodes show, there are always consequences for messing with the timeline, and they are nearly always bad. Without going too deep into the temporal accords and the regulations that govern time travel, it’s safe to say that the whole thing is controlled to stop people from tampering with things they should not, and they have deemed that the Borg's presence within the universe is apparently needed. Besides, as nobody truly knows what the origins of the Borg are, a mission to destroy them in the early stages of development would have been something of a lost cause.
Star Trek: Who Would Win, The Borg Or The Dominion?
The reason is a fairly double-edged sword. If the Borg never existed, then there would never have been the battle of Wolf 359, in which a single Borg cube destroyed 39 Starfleet capital
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