What are the key swing states in the 2020 election, and who is winning the battleground votes?

'DEWEY DEFEATS TRUMAN' mistakenly made the headlines on election night in 1948

Credit:  Time Life Pictures

The 1960 presidential election between Nixon and John F. Kennedy saw 10 states won by less than two per cent of the vote. In 2000, the election results came down to Florida’s win, which George W. Bush claimed by a margin of just 537 votes.

How does the Electoral College work?

All 50 US states and Washington DC have a set number of "electors" in the electoral college – roughly proportionate to the size of each state. 

Each state gets at least three electoral votes because the amount is equal to its total number of Senators and Representatives in the US Congress. Washington DC also gets three electoral college votes, meaning a total of 538 electors form the Electoral College.

California, the largest state, has 55 electoral votes, Texas, the next largest, gets 38. New York and Florida have 29 each.

All but two states – Maine and Nebraska – use a winner-takes-all system, so if you win the most votes in a state, you take its entire haul of electoral college votes. 

Joe Biden’s poll lead over Donald Trump in six key swing states

To become president either candidate needs to win a majority of the 538 electors; ie 270 electors.

While the Constitution does not dictate that electors follow the popular vote, many US states have laws requiring them to do so. These laws have been challenged by electors voting for someone else on occasion, but in July, the US Supreme Court ruled that electors must follow the popular vote in states that have passed such a law.

The electoral college system does usually reflect the popular vote – presidents have won the electoral vote while losing the popular vote just five times in US history. The most recent instance was in 2016, when Donald Trump won the electoral college but Hillary Clinton, his Democratic opponent, won the popular vote.

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