As a dirty anarchist, I see voting as fundamentally deceptive. Like the button at a pedestrian crossing, it's there to give the illusion of control; the traffic will eventually stop for a moment, but on the city's timetable, not yours. Moreover, I see many state practices - harmful military and economic intervention in other countries, domestic imprisonment of drug users - as immoral, and I feel that by voting I lend legitimacy to those practices. It's a small symbolic act of defiance: I can't impede the functioning of government, but at the very least I can refuse to participate in its PR exercise.
However, I've recently found myself unable to give a coherent response to voters who make this argument:
Yes, both parties are bad, but one is marginally better than the other on particular issues - abortion, women's rights, employment rights - so not voting for the slightly better party causes real harm.
My previous response (and I suspect the response of many anarchists) is this: you're claiming that state-sanctioned foreign murder and domestic slavery is less important than a few bones the political machine tosses its citizens every now and then. I used to think that a symbolic blow to state power is worth more than a few political gains. Here's my current response to that:
Choosing an airy symbolic victory over, say, abortion rights is almost always an act of extreme privilege. If you're a white man, you have the opportunity to weigh up harm to minorities and women against your own involvement with the war machine. If you're a minority yourself - or you're pregnant, or you might be pregnant one day - then you don't really have that opportunity. You've got to protect yourself. People who will never be harmed by anti-woman or anti-gay laws can afford not to really think about them. They can disassociate themselves from the real consequences of such laws and consider the issue from a pure, objective standpoint. However, the problem with an objective standpoint (and here I stand on the shoulders of the Great Dane himself) is that to reach it you have to set aside your own subjectivity, all that makes you human - and by the time you're capable of considering things objectively, you've lost sight of everything of real importance.
Well. You might respond that by not voting, you hasten the eventual fall of the state, which will bring serious long-term benefits to women and minorities alike. Here, in brief, is my response:
You're fooling yourself. Sure, not voting takes away a little legitimacy from the state, but you're still paying taxes. Refusing to vote is an act of hand-washing, cleansing oneself symbolically while simultaneously funding immoral practices. Legitimacy is not primarily conferred by the practices with which it sustains itself; rather, at base it is conferred by the possession of money, guns and lawyers. When the state finally crumbles, it will be because it's run itself into the ground, not because a few anarchists are letting their lives (or one day of their lives every four years) be a negligible friction in the machine.
If you don't vote, your illusion of utopia is harming real people, right now - people without the luxury of enjoying masturbatory survivalist fantasies of an anarchist country. You don't have to like it. In fact, if you like voting, there's something seriously wrong with you. But you're ethically obliged to do it.