Vote!

Scott Aaronson points out that the probability of your vote changing the results of the election scales like N^-1/2, where N is the number of people. But the amount of change your vote creates, if it tips the election, scales like N. So the expected amount of change you will cause, by voting, scales like N^1/2. That's a big number, so you should vote. If you live in a big country, you should vote more, although that's irrelevant; if any other country is voting today, the US media has ensured that I don't know that.

Of course, N^1/2 seems a bit high, and it comes from modeling people as flips of a fair coin; Aaronson points out that under a more realistic prior (due to Andrew Gelman), the expected probability that your vote flips the election is N^-1, so the expected amount of change your vote causes doesn't depend on the size of the country.

I won't "officially endorse" anybody. But one of the candidates in the present election trained as a lawyer, taught in a law school for a while, and likes to compare himself to a certain Senator from Illinois. That senator, in order to equip himself to understand the law better, studied Euclid. Being a mathematician, I think this is pretty cool. Who I'm voting for is left as an exercise for the reader.