Don’t be fooled by early returns. There’s a fairly good chance that we won’t know who the top two finishers in the governor’s race are tonight, experts say, which could generate a lot of incorrect punditry, partisan anger and ungrounded conspiracy theories in the days ahead.

The reasons are simple: Even though the polls close at 8 p.m., under California law all 23.1 million registered voters in the state received a mail-in ballot. State law also requires that ballots must be counted as long as they are postmarked by Election Day and arrive at county elections offices within seven days after that. In other words, thousands of valid ballots won’t even have reached election offices tonight.

Last chance to vote. Note that postmarks don't get put on by default for a day or two if you drop your ballot at the post office; you need to explicitly ask them to postmark it if you go there. Probably easier to use a drop box near you