This new Government was primarily formed to regulate ultra-powerful conglomerates. Motivated into action by the barely averted destruction of Earth at the hands of the malevolent and sentient Artificial Intelligence SHODAN (as took place in System Shock), all governments on Earth came together to form the UNN, or Unified National Nominate.
However, both SS games are very unique, as they are the only games I've seen that successfully merge a role-playing game with a first-person shooter, with the possible exception of the more recent Deus Ex. The situation was the same when the Original System Shock was released in 1994: the game was commonly dismissed as another Doom clone, which led to it not getting the praise and respect that it deserved. First, with such a plethora of FPS games available, gamers don't always know how to tell the good from the bad. SS2 overcomes many negative expectations.
This rule of thumb holds true for Irrational Games' RPG/ FPS-hybrid game, System Shock 2. There's a saying that has been passed along in my family for generations: If a game contains malevolent monkeys that attack with psionic shockwaves, the game is good.
