Many worlds
Scott Aaronson at Shtetl-Optimized notes a correlation between libertarianism and the many-worlds interpretation of quantum mechanics, of all things. Many-worlds says that Schroedinger’s Cat, instead of somehow being alive and dead at the same time in this world, is actually alive in one world and dead in another. This is an over-simplification, of course. Since cats have nine lives, a complete many-worlds explanation of Schroedinger’s Cat requires at least ten alternate universes.
Aaronson says the connection is a tendency to follow logical reasoning to extreme conclusions:
The entire world should follow the line of reasoning to precisely this extreme, and this is the conclusion, and if a ‘consensus of educated opinion’ finds it disagreeable or absurd, then so much the worse for educated opinion! Those who accept this are intellectual heroes; those who don’t are cowards.
He also mentions computer nerds and science fiction, and the connection between computer programmers and libertarians is well-known. Eliezer Yudkowski at Overcoming Bias draws a connection between libertarianism and science.
I think the common thread is something closer to “alienation plus logic”, and I don’t mean that in a bad way. Science fiction is pure escapism. The online world is a substitute for the real world. An imagined ideal libertarian world is a substitute for a messy real world. Logical alternate universes are a substitute for a single paradoxical world.