There is lots of confusion in the political arena of ideas about who libertarians are, who they vote for, and which party they belong to. There is, of course, a Libertarian Party, but with its electoral prospects dim as they are, most libertarians choose to align themselves instead with the two larger parties. This is my best estimation of where we end up on any given Election Day.
Most libertarians vote Republican (~67% for McCain in 2008), fewer vote for Libertarian, and a handful even vote Democrat (~30% for Obama in 2008). I think with Mitt Romney's ongoing friendship with the Paul family, socially moderate history, and demographic trends on certain issues, plus a noted (though certainly overblown) Ayn Rand fan, Paul Ryan, on the ticket, libertarians have their best shot in decades of realistically pursuing their goals through the GOP, as I've explained before.
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