Where are the limits?

Lately a lot of folks on this site, including Kos, have been saying with great certainty that Bush won't do certain things. (Canceling the 2008 elections was Kos' example.) We're often urged to take off our tinfoil hats.

I'd love to. Personally, I feel paranoid when I worry about the more outrageous stuff. But all the same, I do worry. My sense that "an American president would never do that" has already been violated so many times that I no longer have good defenses against paranoia.

So I'd appreciate it if those of you who do have such defenses would help me out. If you believe there are definite limits on what Bush will or won't do, where do you think those limits are? And what is your basis for having confidence in those limits?