Rand Paul is a guarantee that another Dem will win. Sad as it is, the demographics in this country have changed to the point that any candidate that is conservative or about freedom and less government doesn't have a chance.
I disagree with that statement for one simple reason - how could we know? It's been so long since there's been a (albeit longshot) contender for the whitehouse that's actually believed in smaller government that there may very well be a large group of people willing to vote for him/her.
I think people have been stuck with picking between the giant douche and the turd sandwich for so long that a candidate that has some real backbone would stand a good chance.