Ethical behavior given the Paradox of Voting

[Measure_for_Measure]

Past threads:
http://boards.straightdope.com/sdmb/archive/index.php/t-455340.html
http://boards.straightdope.com/sdmb/archive/index.php/t-670018.html
Topicality: In some sense this belongs in GD, as it is a matter of political philosophy. But it comes up so much in this forum that I’m leaving it here. Examples:

@PhillyGuy

A presidential election isn’t going to be decided by my vote. In the infinitesimally small probability possibility that it seemed to come down to my one vote, there would be a contested recount with a judicial decision determining.

So it is irrational, or at least highly unreasonable, to vote as if my choice will determine the outcome at the state or national level.

My vote is instead an expression of opinion as to who should win.

Over at Wikipedia, Brennan and Lomasky appear to concur suggesting, “that voters derive ‘expressive’ benefits from supporting particular candidates.”

@puzzlegal

Because Kant. What if everyone in your general situation did that? We’d all be playing chicken, and routinely seeing races between two extreme and incompetent choices. If each party tries to nominate its best, we are more likely to get two competent candidates who are closer to the middle.

Which is the better outcome for the long-term health of the country?

There are other examples. I encourage others to quote them, especially those over the past year or so.