Recently, Republican presidential candidate has been running away from his Libertarian roots as fast as he can. Why is he doing this, when it is pretty well known that both he and his father have long been Libertarians? For a couple of reasons.
First, he saw what happened to his father's numerous attempts to run for president in the Republican Party. Ron Paul probably milked as many votes as possible out of the Republican Party -- but it wasn't nearly enough to make him a contender for the nomination.
Second, he understands (like his father did) that running on the Libertarian Party ticket was nothing more than an exercise in futility. If you're serious about trying to be elected president in the United States, you must get the nomination of one of the two major parties (Republicans or Democrats) -- at least at this point in our history.
Third, while many with Libertarian leanings are posing as Republicans these days, they only make up a tiny percentage (about 13%) of the party (see chart above). They are outnumbered by at least three other groups in the party -- teabaggers, evangelicals, and establishment (business-oriented) Republicans. That's why Paul is trying to re-invent himself -- because he must appeal to these other groups to have a chance.
And Americans in general are much more accepting of libertarianism than the Republicans are. The chart below shows the segments of the population willing to ID themselves as Libertarians -- and as you can see, it's a pretty tiny percentage across the board.
These charts were made from information in a new YouGov Poll -- done on April 8th and 9th of a random national sample of 1,000 adults, with a 4.1 point margin of error.