Donald Trump will face Vice President Kamala Harris in the 2024 election after Joe Biden dropped out of the race in July.
With the election under three weeks away, the campaigns are focusing on the battleground states that will ultimately decide the outcome of what is likely to be an extremely tight race.
What are swing states?
The classification of “swing state” is not official, and pollsters disagree over which states are most important for candidates going into each race.
Broadly speaking, a swing state is where both major parties enjoy similar levels of support among the voting population – with the Democrats and Republicans within a few percentage points of each other in polls.
In this presidential race, the critical states are likely to be Arizona, Florida, Georgia, Michigan, Nevada, North Carolina, Wisconsin and Pennsylvania.
In six of the eight – all but Florida and North Carolina – Mr Biden beat Mr Trump in 2020, giving him a lead that allowed him to win the White House.
Why are swing states important?
Swing states matter because almost all states use a “winner takes all” system for allocating the votes of the state in a presidential race.
Even if one candidate wins by a very narrow margin – as Mr Biden did in Georgia in 2020 – 48 of the 50 states will allocate all of their delegates to that candidate to vote in the Electoral College.
The Electoral College is the body that ultimately determines the winner of a presidential election, by representing each of the states in a vote.
Only in Maine and Nebraska are votes allocated on a more proportional basis, with two delegates instructed to vote for the overall winner in the state, and the remainder asked to represent the result in each congressional district.
The weighting of these votes means that winning a narrow swing state can have a disproportionate impact on the result – making them vital in securing the presidency.
As Hillary Clinton found out in 2016, winning more votes than the other candidate does not mean winning the election. In some states, the location of voters matters as much as their choice of candidate.
Which states have become Democrat?
Mr Biden’s 2020 election victory in Arizona was surprising to some observers, as the state had only voted once for the Democrats since 1976.
The state had voted for Mr Trump in the 2016 election, and consistently voted for the Republican candidate even in elections they did not win at a national level, including in 2008 and 2012.
Georgia, a stalwart Republican state between 1996 and 2016, chose to take a chance on Mr Biden in 2020 and hand him a knife-edge victory that Mr Trump sought to overturn. That incident is now the subject of state legal proceedings against Mr Trump and his team.
In both of those states, Mr Biden’s support now looks shaky – and could spell trouble for him in 2024.
Which states do Republicans need?
The Republicans must win back their former heartlands from Mr Biden, and attempt to win over traditionally Democratic states if their candidate has a chance of winning the 2024 election.
There are already positive signs for the party in Florida – a state once considered one of the closest races, but that has since become more strongly Republican. Ron DeSantis, the second-placed GOP primary candidate, is the state’s governor.
In North Carolina, Mr Trump won narrowly in 2020 and his campaign is looking to extend that lead in 2024, if he is chosen as the Republican nominee.
Winning Pennsylvania, which has voted Democrat in every presidential race but one since 1992, would be a major coup for the Republicans in 2024. Not only has the state been a focus for the Biden administration’s “Bidenomics” policies, it also contains the city of Scranton, the president’s birthplace.
Pennsylvania’s voting history is mirrored in Michigan, which also chose the Republicans in only one election since 1992. The state is the heart of the American automobile industry, and contains hundreds of thousands of blue-collar workers whom both Mr Biden and Mr Trump have targeted in their early campaigns.
Can Harris win the swing states?
Political scientists said they predict a close election, similar to the outcomes of most of the elections this century.
“We have not seen a runaway re-election landslide like the kind that Ronald Reagan and Richard Nixon had, or Lyndon Johnson had at all since 2000,” Christopher Galdieri, a professor of politics at Saint Anselm College, told The Telegraph.
He said that while Ms Harris won’t be “bogged down by Biden’s age” and other negative connotations, in swing states in the industrial Midwest she may not be able to win over the same coalition of voters.
“As a black woman, she’s probably not going to appeal to the white working class voters who saw Biden as, you know, culturally in step with themselves,” Mr Galdieri said.
“I think it’s not that she can’t win there, but I think if she does win there, it’s with a coalition that looks a little bit different from the one that Biden won with in 2020,” he said.