In addition to legal restrictions on when officials can count mail ballots, long lines at polling places at the end of the day can also slow counting, as voters who are in line at closing time are still allowed to vote.

Americans take to the polls today in one of the closest presidential elections in history. Polls have been very balanced, with the election too close to call for either side. Both Kamala Harris and Donald Trump have been campaigning hard in the swing states that will decide the next President.