US poll tracker: Who will win, Biden or Trump?

In the US Presidential elections, each state is assigned a number of electoral college votes, which go to a candidate after winning in that state, irrespective of the margin of the victory (except in Nebraska and Maine).

For instance, in the 2016 elections, Democratic candidate Hillary Clinton led the polls and had 2.8 million more popular votes, yet Trump won the electoral college.

The key to tracking the US elections—and winning them—is to focus on "swing states," that have historically swung between voting for different parties.

The Guardian has been tracking the polls in eight swing states, including Arizona and North Carolina that might emerge as new swing states this year.

The six others include states that went to Trump in 2016, despite backing Obama in 2012.

In six of the eight key states, Biden is leading over Trump, according to The Guardian's poll tracker.

Biden is leading Trump by a margin of 8.8 points in Michigan, followed by Wisconsin (7.3 points), Pennsylvania (5.6 points), Arizona (2.9 points), Florida (1.8 points), and North Carolina (1.6 points).

Trump is leading in Ohio (1.5 points) and Iowa (0.1 points).

It must be noted that the polls, especially in the swing states, had undercounted Trump supporters in 2016. It remains unclear if the polls have corrected this miscalculation despite assurances.

Further, the amount of Democratic support may be over-counted in the polls, since more people say they will vote for Biden than actually turn out to vote.

The elections will be held on Tuesday (November 3). The national polls also show that Biden has a lead of 8.6 polling points.

Notably, this year's elections are expected to have the highest voter turnout in over a century.

Voting this year has been different as many states have allowed in-person early voting and mail-in ballots due to the coronavirus pandemic.