There is the Maquis which are basically insurrectionists/terrorists and Starfleet also has Section 31 for doing wet work.
Sisko poisoned a planet’s atmosphere, allowed political assassinations and even Picard did things that could be considered questionable once or twice, even Kirk.
Earth is peaceful because well…in a show about exploring space nobody really wants to see conflicts on Earth (there are a few exceptions where it worked though). And they have enough big guns and secret assassins to keep up appearances.
Sisko poisoned a planet’s atmosphere, allowed political assassinations and even Picard did things that could be considered questionable once or twice, even Kirk.
Earth is peaceful because well…in a show about exploring space nobody really wants to see conflicts on Earth (there are a few exceptions where it worked though). And they have enough big guns and secret assassins to keep up appearances.