How far did the introduction of The Maquis to the Star Trek: The Next Generation.
With that sense of utopian serenity in place, it's certainly strange than a paramilitary terrorist organization came into existence. The writers and producers of Deep Space Nine.
The Maquis were introduced in Deep Space Nine's second season and were named after French and Spanish World War II resistance fighters, which should provide some idea of the group's intentions and methods. In Star Trek canon, The Maquis are established after a demilitarized zone is agreed between the Star Trek: Voyager, The Maquis illicitly arm themselves and launch guerrilla-style attacks, fighting back against aggression, but ultimately struggling to keep up with the Cardassians.
The Maquis represented the classic "freedom fighter" vs. "outlaw" trope. While some in Starfleet felt that the group were colonists sacrificed for the greater good and left to fend for themselves, others saw them as troublemakers that threatened the peace treaty between the Federation and the Cardassians. This inner conflict put a moral strain on characters such as Deep Space Nine's Captain Sisko, drawing a fine line between doing the right thing and betraying one's own government.
This concept would've been entirely alien to Roddenberry's Star Trek, and anathema to his utopian vision of the future. By Roddenberry's rules, Federation colonists striking back against perceived injustice was been virtually unheard of; something that belonged in the 20th and 21st centuries, but that humanity had grown out of by Star Trek's era. It's entirely possible that, had the franchise's creator been alive when the concept was first put forward, The Marquis would never have been introduced into Star Trek chronology.
While The Maquis certainly could be seen as a betrayal of the original Star Trek world, that doesn't necessarily mean the storyline shouldn't have happened. As much as Star Trek fans hold Roddenberry's ideals in high regard, audiences in the 1990s demanded something different in their science fiction, and with 3 separate shows to plot out, the addition of conflict among the Federation and within Starfleet was necessary if Star Trek were to survive in the long term and adapt for a new generation. Had Star Trek not moved beyond Roddenberry's remit and tackled more modern topics, it's possible that the franchise wouldn't be so popular today.