Four days before Election Day in the US, over 35 million Americans have voted in person, and more than 30 million have already sent in their mail-in ballots.

In Wisconsin, one of the battleground states that could determine the outcome of the elections, over 1 million ballots have been issued. According to the BBC, polls show Kamala Harris narrowly leading Donald Trump by one percentage point—48% to 47%.

Trump has a slight edge in key battleground states like Arizona, Georgia, Nevada, North Carolina, and Pennsylvania. In the other two states—Michigan and Wisconsin—Harris has been ahead since early August, sometimes by two or three points, but the gap has now narrowed.

Michigan, Pennsylvania, and Wisconsin were strongholds for the Democrats before Trump flipped them to his side on his way to winning the presidency in 2016. Biden reclaimed them in 2020, and if Harris can do the same, she will be on track for electoral victory.

As the BBC emphasizes, the individual polls used to create these averages have a margin of error of about three to four percentage points, so any candidate could perform better or worse than the numbers suggest today.

Reflecting how much the race has changed since Harris became the Democratic nominee, on the day Biden withdrew, she was trailing Trump by nearly five percentage points on average across the seven swing states.