Predict the president 2020: Will Trump or Biden win the US election? You decide

Mr Trump won a surprise victory in Wisconsin in 2016 by a small margin, mainly by appealing to rural areas and working-class white women. But this same group of voters helped elect a Democratic state governor two years later - and Mr Biden is currently ahead in the polls.

Wisconsinites may have been put off Mr Trump by foreign trade wars that have strangled exports from the state's many dairy farmers, leading to plummeting prices and farm closures.

The state has been rocked further by violent protests after a black man was shot by police in the city of Kenosha. Republicans warn that a Democrat win would bring lawlessness and further violence. But will Wisconsin voters be persuaded?

Mr Trump scooped the traditionally Republican state in 2016, but his 4% lead was a lot smaller than those enjoyed by Republican candidates in previous elections. This time, pollsters are forecasting Mr Trump will lose to Mr Biden.

The Grand Canyon state has a growing Latino population and an increasing number of rich city dwellers, who both tend to vote Democrat. The state has also been badly hit by coronavirus, so voters who think the president has handled the crisis badly may want change.

But Mr Trump's focus on building a wall along the state's southern border with Mexico, and a crackdown on visas for foreign workers, could still play well with voters.

North Carolina was a Republican stronghold before Barack Obama won with a narrow majority in 2008. That blue blip in a history of voting red suggests that a Democratic victory is not off the cards completely.

Both Mr Biden and Mr Trump have shelled out millions in advertising to try to capture the state, where Mr Biden is leading in the polls.

North Carolina is the first state to begin early voting by post and record numbers of requests for postal votes have flooded in - more than half of them registered Democrats. If mail-in voting swings the final result, things are looking less rosy for Mr Trump.

Mr Trump squeaked out a win here in 2016 with just a 0.3% lead on Hillary Clinton. The traditionally Democratic, working-class state bucked a 28-year trend to elect Mr Trump after he promised trade deals to benefit manufacturing.

Mr Biden, whose father was a car salesman, says he has a deep personal connection to Detroit and often visited Michigan as vice-president. He even considered popular Michigan Governor Gretchen Whitmer as his running mate. Mr Biden's seen as a strong moderate candidate, the type that has always done well in Michigan.

Four years ago, many western Pennsylvanians voted to preserve their way of life, which is reliant on the energy industry, and flipped the traditionally Democratic state for Mr Trump. He promised protection from Democratic promises to reform coal mining and fracking. But has Mr Trump delivered?

Unemployment has hovered in double-digits since the pandemic struck. Mr Biden, who was born in the eastern town of Scranton (more well-known, perhaps, for being the home of Dunder Mifflin Paper Company, Inc. in the US version of British comedy The Office), has long been a familiar face and that personal touch might carry him to victory.

One thing is sure in Florida: its elections are always close. The Sunshine State may be the adopted second home of Mr Trump, but his victory at the last election was no landslide.

The result in Florida is difficult to call because its population is diverse and ever-shifting. The state's large Cuban population leans Republican, but they tend to live in some of the most Democratic counties of the state. Pensioners from other states continue to retire to Florida, and they turn out to vote in droves. Younger voters, who tend to lean Democrat, are multiplying. And suburban voters across the state have been shifting slowly away from the Republican party.

Keep your eyes peeled for Florida's result on election night: in every election bar one since 1964, the presidential candidate who has won Florida has also won the White House.

Georgia has voted solidly Republican in all but two presidential elections since 1960. Yet this year, Mr Biden's campaign team believes he may have a shot. They're betting on support from black voters, who make up at least a quarter of all registered voters in the state.

On race-related issues, Mr Biden polls far better than Mr Trump. Black Lives Matter protests have gripped national news this year, and Georgia's youth have often led the demonstrations outside major cities.

But Mr Trump is pitching himself as the "law-and-order candidate", which could carry weight amongst white, conservative Georgians, who usually drive the state's result.

It all depends on who shows up on polling day.