Suppose you're a person of libertarian persuasion. If you live in a swing state, then your vote for neither Obama nor Romney may have a marginal effect on the electoral outcome. If you do not live in a swing state, then your vote for neither major candidate is, at best, a protest. Perhaps it'll give you bragging rights when things inevitably go horribly awry for whoever happens to be in office. Perhaps it'll amplify in some infinitesimal way the visibility of third parties in this two-party nation and thereby nudge our system toward acknowledging their existence in potentially consequential ways (such as inclusion in the debates).
Then again, perhaps your vote for, say, the Libertarian Party, if cast, will be entirely misguided and even detrimental to the small-'l' libertarian cause.
At the Volokh Conspiracy, a crowd we consider kindred spirits, Ilya Somin has previously made the case that a vote for the Libertarian Party is not only a wasted vote, but a vote contrary to the interests of the one and (so far) only mechanism by means of which actual libertarian influence has been exercised to good effect: working within the major parties to move their ideological centers of gravity freedomward:
Libertarians have had some genuine successes over the last 35 years. These include abolition of the draft (heavily influenced by Milton Friedman's ideas), deregulation of large portions of the economy (of which libertarians were the leading intellectual advocates), major reductions in tax rates (facilitated by libertarian economists, libertarian activists, and the legislative efforts of libertarian-leaning Republicans), the increasing popularity of school choice programs, increases in judicial protection for property rights, gun rights, and economic liberties (thanks in large part to advocacy by libertarian legal activists), and heightened respect for privacy and freedom of speech (promoted by libertarians in cooperation with other groups). Libertarian academics and intellectuals have also done much to make libertarian ideas more respectable and less marginal than they were in the 1960s and early 70s.
What all these successes have in common is that they were achieved either by working within the two major parties or by efforts outside the context of party politics altogether. The Libertarian Party didn't play a significant role in any of them.
This line of thinking is part of an ongoing reflection in those parts on whether the Libertarian Party does more harm than good to the general pursuit of its espoused goals.
Most recently, Somin has argued that libertarians ought not to vote for Gary Johnson:
I certainly understand that some libertarians might want to support Johnson simply to express their views, regardless of whether or not it actually helps advance our cause. But I am skeptical that such “expressive voting” is the way to go. …far better to do it through blogging, public debate, research, or just discussing politics with your friends and acquiantances, working to win them over to your point of view. If we choose to vote, however, I think we should vote for the least bad of the candidates that have a realistic chance of winning. The chance that your vote will be decisive is extremely low, but still just barely high enough justify taking the responsibility seriously.
So then…. What do you make of his argument? Does the so-called "protest vote for Johnson" have value? If so, does it have more value than a vote for "the least bad of the candidates that have a realistic chance of winning"? How might we decide? Must a rebuttal of Somin ultimately hang on emotional, subjective, or aesthetic factors?