In Ohio, a crucial swing state, more than 2.3m postal ballots have been requested, double the figure in 2016.
Reports indicate that registered Democrats have so far outvoted registered Republicans – casting more than double the number of ballots. And of these early voting Democrats, women and black Americans are voting in particularly high numbers. Some are motivated by dislike for Donald Trump, while others have been energised by racial justice protests throughout the summer following the police killing of George Floyd in Minnesota.
But this early advantage does not mean that Democrats can already claim victory. Republicans, who claim postal voting is vulnerable to fraud, say Democrats may win the early vote, but that Republicans will show up in large numbers on election day.
According to a 2017 study by the Brennan Center for Justice, the rate of voting fraud overall in the US is between 0.00004% and 0.0009%.
The enormous numbers of voters have led to long lines, with some people waiting for up to 11 hours for an opportunity to vote.
Younger people, who historically have been difficult to get to the polls, appear to be turning out in larger numbers this year. The youth vote may be the highest its been since 2008 for the election of Barack Obama – the country’s first black president.
A recent survey by Axios found that four in 10 university students said they planned to protest if Mr Trump wins. Six in 10 said they would shame friends who could vote but choose not to.
By contrast, only 3% of surveyed students said they would protest if Joe Biden was elected.