The Paradox of Voting, simply stated, is that voting in a large election almost certainly isn't worth your time (unless you think it's the most fun thing you could be doing). The guaranteed opportunity cost of going to vote will in most cases easily and predictably outweigh the expected benefits — the chance that your vote (along with everyone else's) would be pivotal because the margin was 1 vote, multiplied by your expected marginal utility payoff from your chosen candidate winning.
There are various well-known responses to this issue, listed in the Wikipedia article linked above. But to me, one of the obvious responses is to see this as just another instance of a chicken/snowdrift game, and to invoke the logic you might use to support cooperation in such games; that is, decision theory. I think this may even be one of the most common real-world instances where UDT/FDT might apply. I think it would also be a source of interesting edge cases for exploring the limits of UDT/FDT; that is, even small changes in how strictly you delimit which other (potential) voters to consider as UDT/FDT "co-agents" could easily swing the prescriptions you'd get. But doing a few quick google searches doesn't turn up any write-ups considering this issue in this light. Am I missing something, or is this idea really "new" (at least, undocumented)?
ETA: Thanks to @Vanessa Kosoy, @Daniel Kokotajlo, and @strangepoop, I now have sufficient references for prior discussions of this idea. Thanks! Honorable mention to @lkaxas, who suggested a connection to Kantian ethics which is relevant, though more remote than the references given by the above three.
I think it's just reachability. Arbital is Far Away, and it's plausible that not everyone even knows it exists.