By this point four years ago, more than half of the returned ballots came from Republican voters. The Clinton campaign has put a heavy focus on targeting the early vote in North Carolina and elsewhere, which may help play a role. But notice, too, that far fewer Republicans have returned ballots so far — compare the red line under 2016 with that under 2012 (or 2008). By that point in 2012, there'd been a big spike in ballots returned by Democrats, and that hasn't happened this year. In Florida (for which 2012 data wasn't available), the margin between the parties is much narrower, while the number of returned ballots is much larger.

Source: Washington Post October 21, 2016 12:53 UTC