When a Presidential candidate votes for President, is there any sort of tradition where they vote for themselves or vote for the other guy?
Write-in.
In general elections, politicians vote for themselves (as far as we know, since it is a secret ballot).
Well, I know they don’t vote for me, because I’ve never gotten any votes.
It’s traditional to vote for yourself in politics. If you wouldn’t vote for yourself, why would you expect anyone else to do so?
The notion of voting for the other guy is some kind of weird remnant from the days when “gentlemen” were supposed to be modest to a fault. It’s not an American tradition generally and I’ve never heard of it associated with politics.
When a legislative body elects a presiding officer, the party leaders will sometimes cast courtesy votes for each other, or vote “present” as when the US House elects a Speaker.
In general elections, the modern tradition is obviously for politicians to vote, and we have no reason to doubt that they vote for themselves. (Presidential candidates, when asked, invariably quip “I voted for [VP candidate] and his/her running mate.”)
However, this was not always the case. David Herbert Donald, in his biography of Abraham Lincoln, relates that Lincoln chose to vote in the election of 1860, because the local elections in Sangamon County were expected to be very close. However he made it a point to tear the presidential electors off of his ticket, because it was considered unseemly in that era for a politician to vote for himself.
I don’t know when this changed, but I suspect it was with the introduction of the more secret Australian ballot.
It’s also a David Letterman joke. In 1992, he did a “Top Ten Reasons Why Clinton Won the Election” and one of them was “Bush fell for the old ‘I’ll vote for you and you vote for me’ trick”.