Some commentators take an emotionalist position on this topic. For instance:
Voting is a privilege and a right given to us by virtue of living in a free society — we don’t need a rational choice framework to provide a reason for participating in the process.Of course, this doesn't answer the question at all. Why should I consider voting to be "a privilege"? Why would it matter if I didn't vote?
Other commentators have attempted to answer this question rationally, but I still find their arguments wanting. Here we focus on probabilities and expected payoffs.
The main problem to be overcome is that there is a very low chance of a voter influencing the election (about 1 in a million for the Presidential election, if the voter is in a battleground state). Sometimes people have more influence, such as pundits or multi-millionaires who can sway a substantial number of votes, or when the electorate is small. But most regular people -- no matter how smart and informed -- are not going to have substantial influence on the election.
The way to overcome this lack of influence is to focus on the scale of the benefit, should we sway the election. If we figure that one candidate is $1.5 billion more valuable than the other (i.e. $50 per American), then the one in a million chance of swaying the election seems pretty good. Based on these numbers, I figure my vote is worth $1,500; I'd give up an hour of my time to get that lottery ticket.
My concern is that this "deal" quickly falls apart once we realize that buying that ticket is not as simple as walking to the voting booth, waiting in line, and casting my vote. There is actually a risk that I will vote for the wrong candidate, and end up costing America $1.5 billion. Yikes. In fact, a quick analysis indicates that I have about equal chances of getting it right or wrong in the Presidential election. Basically, since I'm not a partisan fanatic, I have to assume that most voters are just as smart and altruistic as I am, yet about half of them would choose the other candidate. Clearly, selecting the right candidate is not a simple decision. Ironically, the situations in which I'm most likely to affect the outcome of the election are the very situations when I would have the least confidence in my decision (i.e. when the vote is evenly split).
Having realized the responsibility that I bear as a voter, I could decide to collect more information about the candidates so that I am able to make an informed decision. Even if I cannot go into the voting booth with absolute certainty in my decision, perhaps it is enough to increase my confidence to 75%, or even 60%. Maybe it's worth voting even if I only have 51% confidence that I am choosing the right candidate (2% of $1,500 is $30).
But how can I make a reasonable choice about candidates. I can watch debates, read their ideological statements, and the policy proposals. How much will this help? Will I select a good President, or just the best con-man? Will the newspaper articles really reveal the character of these candidates, or will they just reflect which candidate has the best PR team and is the best at manipulating reporters? The final fact that I have to face is that all of these candidates are strangers to me, and I can only gain a very superficial understanding of them even if I dedicate all of my free time to investigating them. Is there anything better I could do with my free time?
On almost any criteria I can think of by which to evaluate the candidates (e.g. policies, parties), I run into the same problem -- the situation is incredibly complex and far removed from my direct experience. To top it off, and I can't really trust half of the information that I get since it is clearly being manipulated by the candidates and their supporters. I'd end up spending hundreds of hours studying just to get my confidence up by a couple of percent. There is some consolation in the fact that I'd likely do much of this studying anyway (I'm a news junkie), but I'm sure that I could spend my time more wisely than that -- I could spend time with my family, on my job, or volunteer with a charity.
After all this, I still have some hope that voting is worthwhile -- perhaps as a signal to the President that he does not decide when to leave office. But I'm not sure it matters who I vote for. Maybe if I am presented with a truly despicable candidate (e.g. Santorum), I would vote as if the election depended on it, but otherwise, I can't see the point in taking the decision too seriously. If I were to vote seriously, the best strategy that I can think of is to vote on a single issue.
Luckily, this mess clears up a little if we think about smaller elections: as things get more local, my influence increases and my information also increases, even if the stakes decrease. This reaches an extreme with my decisions in my personal life, where I confidently make plenty of low stakes decisions that cumulatively provide massive welfare benefits for myself and others.
The decision to vote or not (and how seriously to take it) is simple enough, but this attitude that voting is sacred permeates our culture and twists our institutions. This is most evident in the way that newscasters obsess over politicians: how much real news are we missing because the newscasters think that national electoral politics is the most important thing in the world? How many science and technology stories are going unreported? How many local stories are ignored? How much energy are we wasting on national politics?