Per Wes's election post, not voting because you don't like the available options fails to grasp the reality of our situation. There are plenty of principled rationales for ruling out both candidates, and you may think that not voting, or voting for a third-party candidate, will send some kind of message that the system is too flawed for you to dirty your hands with. There are plenty of online versions of this, though since one of our listeners sent me one from Aladsair MacIntyre from eight years ago, I'll refer you to that as one example.
The ethical tussle here is as old as principled Kantianism vs. calculating utilitarianism, where followers of the latter ridicule the former for their naïveté and/or their stubbornness. Certainly in our episode about the American founding I was in despair about a system that seems to have failed to live up to Madison's hope to reign in factionalism.
To balance my attitude there, I feel the need to point out that today's political parties are not factions, but are already coalitions between factions. It's often been commented that the alliance between social conservatives and economic conservatives seems strange and unstable, and the same can be argued for the partnership between union workers and the liberal intelligentsia. In trying to motivate voters, the candidates have often attempted a positive vision, but in trying to come up with something truly unobjectionable to all their actual and desired supporters, these have been strange: along with the expected and ambiguous advocacy of liberty (what kind?) and prosperity (how?), we see candidates more picking out large groups than issues: "I'm fighting for the middle class!", "I'm fighting for small business!" (Both of them say both of these things.) It's seen as a failure (by some pundits) that these guys can't rally us all around some vivid, coherent utopian vision.
If you listen to Madison, though, you shouldn't expect this. People are motivated largely by their factional interests, by what profession and social class they're in, what religion, what part of the country. Putting aside the fact that people are often duped into voting directly against some of these factional interests, we would expect on Madison's view that the desired futures of these various and disparate groups would be too at odds with each other to allow them all to support any particular vision. We philosophy types can argue for some utopia based on ideas about human nature itself, but folks that can't or don't see the point in abstracting from their concrete situation to think like this just want policies that will benefit them and their causes. (The relation between one's sense of self and ones values, where the things we value are in fact ascribed to be part of the self, is again, of some importance here, but needs to be set aside for brevity's sake.) Madison was correct in thinking that this fact about our desires makes it unlikely that we'll actually have a pernicious majority faction that can run roughshod over the minority. If every group would ultimately like everyone else's wealth and power handed over to them in particular, then the competition between groups means no one group will pull this off.
However, while we may not be able en masse to agree on what we want done, we can achieve a great deal of agreement between many different factions on what we don't want done. Liberals don't want corporations and the rich taking advantage of us. Conservatives don't want the needy ganging up on the rich and distributing all their stuff, and/or don't want "experts" denying religion it's proper place in setting social policy. If one of these is your primary concern, then you are fully justified in voting against the the one most likely to promulgate this evil you've identified. It would be nice if the guy you actually vote for has a vision you want to sign on to, but what unifies the coalition--and thus is needed to win the election--is the drive to prevent the evil schemes of the other side.
Participating in this process is thus not dirtying your hands, not betraying your principles, not giving a big mandate to the person/party you vote for, but just trying to make things less bad. So let's everybody (international readers excluded) get out and vote for the least bad candidate! Woo woo!
(The image is a reference to the South Park episode on the 2004 election, "Douche and Turd." I must say that I actually don't share the harsh dismissal of both candidates that many routinely display, and though I'm pretty horrified about the whole drones and kill lists thing, I would likely vote for Obama even given plenty of other choices, and did so in the 2008 primary. At least neither candidate is an idiot man-child this time.)