Because one of Roddenberry's rules for both TOS and TNG stated that the Enterprise crew members were not allowed to fight among themselves............when Deep Space Nine first aired, many people considered it a risk in some regards because it changed a fundamental aspect of what many considered an important part of Trek, namely, the idea of space exploration. The premise of DS9 turns the accustomed starship setting into a static space station that can't go anywhere. Rather than seeking out new life, this series is primarily about a Federation team building a relationship with one civilization, the spiritual Bajorans. The Bajorans have recently liberated themselves from the Cardassians, who had occupied their world for 60 years. DS9's storylines are in many regards much more complex than those of either TOS or TNG, because they deal with drawn-out relationships and political situations within the context of a single culture, as well as the impact on that culture when outside political developments threaten its well-being.