OMG: The Revenge of the Sith

[Kamog]

One thing I don't understand from episodes I and II is, if Senator Palpatine is the Sith Lord, why don't the Jedi sense the dark side in him? I assumed that Palpatine is able to hide his power somehow.

Or maybe there's some sort of trick where Palpatine is actually not Darth Sidius, but a clone?

Also, the rule about only two Siths existing at one time doesn't sound like such a good idea. There's a master and an apprentice, and that's it? So the master has to die before the apprentice can call himself the new master and take on a new apprentice.