When I say that the probability of throwing 3 heads in succession is 1/8, that refers to the fact that if I toss three coins a large number of times, I believe that the number of times I get three simultaneous heads will asymptotically approach a ratio of 1/8. Each individual throw is of course governed by well understood mechanical laws, but the sequence of uncontrolled tiny effects at the start of and during each coin toss effectively produces a pseudo-random result.
When I say the probability of Ron Paul getting elected is small, I don’t refer to an ensemble of identical events at all. Randomness doesn’t come into it either. I think that what I really mean is that I CANNOT EASILY IMAGINE A PLAUSIBLE DETERMINISTIC SERIES OF EVENTS THAT WILL CAUSE THAT TO HAPPEN.
These are two very different uses of the word probability. There should probably be a different word for the second use. All of this makes me increasingly suspicious of the use of probabilities in describing societal events.