Tim Minear, High Lord of the Whedonverse, writes:

While I’m certainly flattered that your friend credits me with any libertarian/conservative influence on “Firefly”, or even the larger Whedonverse, I didn’t create “Firefly.” Joss did. Mal was always a libertarian leaning character and he was born utterly from Joss’s giant brain. It’s not like it was Collectivists In Space! before I came along. Mal was not my creation, I just got to wear him for a while– and turned out he fit. If Joss could only write from the point of view of characters with which he agreed, he wouldn’t be Joss. Though I did come up with the whole “vampire slayer” thing. Not that Kerry-boy would ever admit it.

Update: Glenn Reynolds has a podcast where they talk with Minear re politics etc.