Voting is important. Tomorrow I'll be voting in my 39th consecutive election. When I vote for candidates, they rarely win. The ones that do have without exception disappointed. Many elections don't have any candidates I want to vote for. So I spoil my ballot.
There are a lot of shitty reasons to vote, and there's reason to think low-information voters can be dangerous. After all, winning candidates acquire real political power over all of us, not just those who vote—being a low-information voter is one of several great reasons not to vote. Trying to intimidate people into voting, as some groups around the country are doing this year, is ridiculous. Ultimately your vote matters very little. It's almost certainly never going to tip an election. Many elections (think 2012) don't really have a plausible conclusion that doesn't suck for the American people. Nevertheless voting is important, because in a democratic system the absence of a vote enforces the illusion of the consent of the governed.
Most people don't vote. The U.S. population is about 316 million. About 235 million are adults. 146 million are registered to vote, about 71 percent of those eligible. About 130 million Americans voted in the 2012 presidential election, nearly 66 million for President Obama. He received 51.1 percent of the vote, one of the worst showings of a winning presidential incumbent ever. But that represents just 32 percent of the eligible adult population. Almost all of the 49 percent of voting Americans who didn't vote for Obama voted for the Republican, Mitt Romney. That still leaves at least 78 million Americans eligible to vote who didn't vote for Obama or Romney, more than the vote total either major party candidate received.
It's impossible to say how many of those 78 million Americans, pressed to vote, would vote Democrat or Republican. Get out the vote efforts by Democrats, however hamfisted, suggest they believe they have an advantage in higher turnout. Millions of Americans, however, may never vote precisely because they don't like Democrats or Republicans. A lot of people don't know they're libertarians. A lot of libertarians don't believe in voting.
And not every Libertarian candidate will appeal to all libertarians. Certainly not every adult eligible to vote will have a candidate that matches up even imperfectly with their own views. There are other options—blank ballots, spoiled ballots, write-ins (usually). In some jurisdictions the write-in vote has been abolished. Usually this is accomplished through first round voting that includes more than one candidate per major party and a run-off limited to the top two. That set-up, along with other systematic way third party and independent candidates are excluded from the process, is made possible by enough non-voting. The presidential debates don't include third party voters because likely voters, who happen to be the likely viewers of a presidential debate, aren't particularly interested in them.
No one person's decision to purchase or not purchase an Apple phone over an Android phone will make or break Apple. No one person's decision to buy a smartphone, period, will affect the price of any phone on the market. Yet, in the aggregate, market participants set prices. Even the non-participants, those who decide not to buy, help set the price by not exerting more demand-side pressure. Politics is different, because it's forced. Free markets are supposed to be voluntary. It's how they are able to work, to self-regulate, how companies and consumers can match up in mutually beneficial ways. Not purchasing a smartphone deprives no one of anything but you of a smartphone.
In politics, on the other hand, not voting becomes part of the illusion of consent. After all, non-voters aren't starting insurgencies or calling for revolutions (unless they're selling books, maybe).
The consent required for government to exert more control over you is far less robust than, say, the consent demanded of college students in California, or, actually, in any other situation where consent is required.
Voting is a right, not a privilege. It's also not something you have to exercise. Not voting doesn't diminish anyone's credibility in criticizing the system, because voting doesn't ensure a specific result. But the regularity of not-voting helps promote the idea that the system is acceptable, just as much as the regularity of voting for the major parties does. Breaking that cycle can help break politics' control over us.