A one-vote win is rare even in local or state races, which attract smaller turnout. The largest numbers of voters — about 6 in 10 eligible adults — come out for presidential years. Yet the presidency’s never turned on just one vote, not even in the 2000 recount that flummoxed Florida.

It’s so improbable that scholars debate whether voting is a rational act.

“There is no question that from a simplistic rational view it doesn’t make sense to vote,” said Kevin Lanning, a political psychologist at Florida Atlantic University. “Even in Florida I’m more likely to be killed in an auto accident going to the polls than I am to cast the deciding vote in the presidential election.”…

[Gelman] says voting can be a rational investment of time. That’s partly because the outcome affects so many people. It’s like entering a lottery that you almost certainly won’t win, but if you do win, all 315 million Americans share your jackpot — the president you believe will do more for the country.