As I left my driveway to vote this morning I realized I was already a dead man. I passed more than one sign for the candidate I did not support, proving that my vote had already been cancelled out. But if I did not cancel out one of theirs I would not have done all I could to support victory for the side I choose.
In the final tally the margin is what matters. The majority of voters have to go out and fall in single combat to allow a few survivors on one side to stand as the margin of victory. Fortunately, the death is only metaphorical. You could count yourself as part of the margin rather than the anonymous pile of bodies on which it stands, if it makes you feel better. Just make sure you get out there and add to one group or another.