Conspiracy Theory Games

If you're still reading this thread, you can't do much better than a game called Control.

Sounds like you've already got the primary theme of your game solidified, so all you really need is an engine that emphasizes conspiracy theories.

I have a copy, but I'm pretty sure it's out of print. I've never seen it for sale ANYWHERE except online, briefly, which is where I bought it.

Essentially, characters are motivated by one of the seven sins, and have a about a dozen traits that describe them. There's very little setting information provided, but there's a mechanism by which players can attempt to wrest GM control from the current GM, thereby imposing their own interpretation of events into a conspiracy.

Makes for VERY convoluted plotting and counterplotting as different players literally "take over" GM-ing and try to make their conspiracy/conspiracy effects dominant.

If there's any interest, I'll post some more details on the game.