Palpatine's scheme fed on sentiments that were already in place. A lot of worlds in the Republic (Core Worlds in particular) already had pro-imperial and anti-Jedi sentiments. In fact, I'm betting that a Galactic Empire was an inevitability minus Palpatine, although few would be better suited to run it than he was.
Also, Palpatine was indeed clever but his entire schemes rested on how moronic the Jedi were (c'mon, the Clone Army should have made the Jedi far more suspicious than they were). Had they any brains (let alone any Republic security ministry or such) he probably wouldn't have gotten as far as he did.
And yes, we saw something similar to this happen. It's called Nazi Germany.
As of 3/14/10, TSL is restored. The Sith Lords Restored Content Modification by Stoney and Zbyl has been finished and can be downloaded here