Matthew Yglesias makes the best bet yet for voting for the nuttier-than-usual libertarian. On the one hand, one could counter that it's important to teach the libertarians a lesson too; what other people view as a more or less indistinguishable mess of nuttiness actually has much different levels, and the party really needs to learn that you can't just slap the libertarian label on an otherwise unacceptable candidate. On the other hand, there's a decent case that the LP is particularly resistant to incentives.
I think the way to teach the Libertarians (capital 'L' please) a lesson is mercilessly to mock Badnarik and the laughably poor judgment of the LP while simultaneously imploring those who might otherwise vote for Bush (why? WHY?) to throw their vote away (which, after all, is about as costly as throwing a used Kleenex away) for a good cause. For the futile purpose of sending a message to the GOP, Badnarik isn't a candidate so much as a value of a variable. I'm voting for the variable. The LP certainly does need to know that if they want genuine intellectual and moral support from the non-black helicopter set, then they need to saturate their variable with less embarrasing values, if you get my drift.
Now, it is true that LP true believers are quite accustomed to being mocked relentlessly, and so the incentive effect of endless verbal pummeling may feel to them like nothing wrose than home. Yet it is possible that some may be persuaded that if one is going to nominate a candidate for President of the United States of America, one might want to have more in mind than the narcissistic expression of one's imagined purist virtue, which is good for little more than reinforcing one's own sense of ideological matrydom.
In an election like this one, a strong LP candidate could very well have a Nader effect and throw the election to Kerry, which, considering the happy consequences of divided government, is what we ought to be hoping for anyway. The choice of a dork like Badnarik may well have botched a historic chance for the LP to actually matter.