Unlike Barack Obama's selection of Joe Biden, John McCain's choice of Sarah Palin seems to have been largely driven by campaign calculations. From an electoral point of view, she brings three assets to the ticket: she's a woman, a staunch conservative, and relatively charismatic. Her gender will give McCain some favorable headlines and perhaps a chance to pick off some pro-Hillary Clinton Democrats and moderates. I'm skeptical that many women or feminists will switch to the GOP ticket merely because the Republicans have a female veep candidate and the Democrats didn't nominate Hillary. But if a few do, it could perhaps make a difference in a close election. Palin's conservatism will help shore up the support of the GOP base, which isn't exactly thrilled with McCain. Finally, her charisma will help in TV appearances and in debates. Since she's articulate and a onetime beauty contest winner, she will certainly cut a better media image than Biden. Though no one else on either ticket this year can match Obama's star power.

As I've argued in the past, the most important attribute of a veep candidate is her potential as a possible future president. How does Palin stack up on this score? In my view, she has one big positive that has to be weighed against a major potential negative.

The big positive is her apparent support for limiting government power. As co-blogger Todd Zywicki notes, she has gone against Alaska's ubiquitous political culture of porkbarrel spending and advocated major cuts in government spending. Sadly, this is an exceptional accomplishment in today's "big government conservative" GOP. Her record in this regard certainly isn't perfect, but it is impressive relative to that of most other prominent politicians in either party. Moreover, the fact that her stands on these issues went against the preferences of powerful interest groups in her state suggest that they are at least to some extent genuine and not solely the product of political calculation. Radley Balko - who is generally very critical of the Republicans - writes that Palin "seems to be about as good a pick from a major party as libertarians could hope for." I tend to agree.

The negative is her lack of experience with foreign policy issues, which are arguably the central focus of the modern presidency. No amount of Republican spin can dissipate this weakness. However, it may be partly mitigated by the fact that she will likely have some time to learn these issues on the job before she has to assume the presidency (if she ever does). Moreover, history suggests that there is at best a weak correlation between prior foreign policy experience and performance in office. Lincoln and Reagan, among others, did an excellent job of managing foreign policy despite having little or no prior experience with such issues. Dick Cheney probably had more foreign policy experience than any other recent vice president; yet his performance in office was far from stellar. Overall, I think that ideology and general political competence are stronger determinants of political leaders' performance in office than issue-specific experience.

Sarah Palin probably would not be my choice if I had the luxury of picking a vice presidential nominee without reference to campaign calculations. Nonetheless, I am guardedly optimistic about her. She seems to be a skillful politician and her positions on size of government issues strike me as a good deal better than what we have gotten from either party in recent years. The idea of a President Palin is more appealing to me than President McCain, President Obama, or President Biden. That, of course, may not be saying much given my grave reservations about all three of the others. Still, I look forward to having her as a VP or as a leading contender for the presidency in 2012 or 2016.