Presidential Candidates - My Early Choices

The Democrats and Republicans held their initial presidential debates over the past two weeks. Mostly, it was political posturing and a lot of dancing around touchy subjects. There were two candidates that stood out to me: former Senator Gravel (D-AK), and Congressman Dr. Ron Paul (R-TX). I would love to have a mixed party ticket with these two guys; they both spoke honestly and took their fellow running mates (and the administration) to task. Why is it that my choices for public office always seem to lose?