all FEMA needs is a national emergency. then they can do whatever they want with everyone.

Zarcoff - have you ever played the original Deus Ex? that game is fucking creepy. FEMA, and MJ-12 get in cahoots with a the CEO of a huge corporation, and start a grab for the world. and all it took was a manufactured virus becoming a national epidemic, and some little bits of "vaccine" being flaunted here and there, for black mail.
it's all disturbingly realistic in concept, with a deliciously twisting, turning, storyline and it's got an interesting RPG/FPS cross breed premise. you should absolutely check it out.