Others will have a lot more to say about Barack Obama's choice of Biden than I do. For now, I will make just three brief points. First, as with most Veep picks, we should focus more on Biden's potential as a possible future president than on his possible impact on this race. As of today, Biden has become a leading contender for the Democratic nomination in 2012 (should Obama be defeated this year) or 2016 (if Obama prevails in 2008).

Second, it seems to me that Obama's choice of Biden reflects confidence among Democrats that they are going to win this year and don't need any boost from the VP pick to do so. Biden is not particularly charismatic, won't enable the Democrats to win any states they wouldn't take otherwise (Delaware is a Democratic lock anyway), and is just as liberal as Obama (therefore with little ability to attract moderates). Virtually his only political assets are his being a white male (which might perhaps reassure some traditionalists or relatively mild racists), and his having more political experience than Obama. There are many candidates that Obama could have chosen that would have brought greater electoral advantage, such as Senator Evan Bayh of Indiana (a well-respected moderate who is more charismatic than Biden and might have put a traditionally Republican state in play).

Third, the choice of another very liberal senator as veep is one more sign that Obama has little intention of moving to the center anymore than is absolutely necessary to win the election. The selection of a prominent moderate such as Bayh or former Iowa governor Tom Vilsack might have been of some small reassurance to people like myself who fear a vast expansion of government should Obama win the election and get the chance to govern with a strong Democratic majority in Congress.

In fairness, even if Obama had picked a moderate, I would still put more faith in the power of divided government to stem the growth of the state than in the potential influence of a moderate veep. This year, the only hope for divided government is a victory by McCain, no matter how flawed he is in other respects. However, not all libertarians and pro-limited government conservatives are as committed to that view as I am. Some of them are supporting Obama or are at least open to doing so. It is perhaps of some note that Obama decided to deny us even the modest hope that could have created by picking a moderate veep who could have been expected to press for centrist policies.

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.

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.