In my initial post on Sarah Palin, I was encouraged by the fact that she seems to be much more libertarian than most other prominent politicians. In this column, David Harsanyi of Reason shows that she has a fairly libertarian record on a variety of issues.
Obviously, Palin is far from being a consistent libertarian across the board. But she has fought to reduce government's role in the economy during her time as governor of Alaska. And even on "social issues" where she diverges from libertarianism because of her conservatism, she seems to support decentralization and a degree of laissez-faire. For example, as Harsanyi points out, she does not favor government-imposed teaching of creationism, but wants parents to be able to choose their children's schools for themselves. As an atheist, I have a lot less sympathy for creationism that Palin seems to. But I agree with her that the overall quality of school curricula is likely to be better with school choice and competition than if they continue to be dictated by the state.
Ultimately, I think that the main libertarian argument for McCain-Palin is based on the general benefits of divided government rather than on the details of their records. To the extent that the latter count, Palin's virtues are counterbalanced by McCain's many flaws; after all, he's the one running for president. Still, Palin's presence on the ticket makes it marginally more appealing from a libertarian perspective.
UPDATE: I am told that David Harsanyi is in fact employed as a columnist with the Denver Post, though he is also a Reason contributor.