In less than a week, millions of Americans will cast their vote to determine whether Joe Biden will become the 46th US President, or whether there'll be another four years of Donald Trump.
But to win the White House, the winner of the US election will have to come out on top in a system known as the Electoral College.
What is the Electoral College?
While it may sound like a university for budding Antony Greens, the Electoral College is a group of representatives who meet to determine who will become the next US President.
It may appear that voters get to decide at the ballot box whether Donald Trump or Joe Biden assumes office, but in reality, Americans are in fact voting for people on the Electoral College who will elect a President on their behalf. The Electoral College meets in December, long after the US election on November 3, to formally vote for President.
How does the Electoral College work?
In order to win the White House, a presidential candidate needs to win a majority of the Electoral College vote.
There are 538 members of the Electoral College, so to win, candidates need to reach the magic mark of 270 votes.
The number of electors from each of the 50 US states, plus Washington DC, is determined by the number of representatives that state has in the US Congress.
Each state gets two senators, regardless of their size, while the number of representatives in the House of Representatives is determined by a state's population.
The largest state by population, California, has 55 Electoral College votes (53 in the House of Representatives and two senators), while the smallest state, Wyoming, has just three electoral college votes (two senators plus one in the House of Representatives).
Whichever candidate gets the most votes in a state, they get all of that state's Electoral College votes. It doesn't matter if a candidate wins by a single vote or 10 million votes. If they have more votes than their opponent, they get all the marbles.
It's why some swing states like Florida (29 Electoral College votes), Pennsylvania (20 Electoral College votes) or North Carolina (15 Electoral College votes) are important because they have a lot of votes up for grabs.
There are two exceptions to the winner-takes-all approach. Both Maine and Nebraska distribute their four and five respective votes based on the proportion of votes a candidate receives.
Can you win the election without winning the popular vote?
While you have to win the popular vote in an individual state to claim their Electoral College votes, it is possible to get the right combination of states to reach the total of 270 without winning the popular vote nationwide.
Famously, Hillary Clinton received almost 3 million more votes than Donald Trump, but Trump won the Electoral College vote 304 to 227.
At the 2000 election, Democratic candidate Al Gore won the popular vote by 543,000 votes nationwide, but narrowly lost the crucial seat of Florida to Republican George W Bush, which gave Bush the narrowest of victories by claiming 271 Electoral College votes to Gore's 266.
There have been three other elections where the candidate who lost the popular vote became President thanks to the Electoral College system. Among them include John Quincy Adams in 1824, Rutherford B Hayes in 1876 and Benjamin Harrison in 1888.
Why was it set up?
When compared to other western democracies, the American system of the Electoral College appears to be an anomaly.
Former head of the political science department at the Australian National University John Hart said the voting system was born out of a political compromise when the US Constitution was first drafted in 1787.
"It was designed so that the choice of who became President wasn't in the hands of the masses, because the founding fathers had a conception of the president as someone who was above politics," Dr Hart said.
"They were tremendously suspicious of the capacity of the ordinary man to participate in government. "It was basically an anti-democratic device to keep the choice of the president out of the masses."
The system was also put in place to prevent large cities ultimately deciding the winner of the presidency in a popular vote due to their large population.
Each state selected their own method of choosing electors for the Electoral College. While some states had a popular vote to choose them, in most cases, it was decided by state legislative bodies.
"There was some demand that the choice of president be made by people who had experience in statecraft and government," Dr Hart said. It wasn't until the 1820s and 1830s that a popular vote for Electoral College members was more socially accepted.
Can a member of the Electoral College go rogue?
With the Electoral College formally deciding who becomes the next US president, there is the perennial question of what if someone on the college votes for a different candidate that their state elected.
Such a person is known as a faithless elector, and while rare, there have been more than 160 incidents of it happening in the more 200 years the system has been in place.
Faithless electors are rare, however, with the major parties selecting who would represent their state at the college, should their candidate win, months in advance, and are often chosen due to their status in the party, and to break from party lines would be seen as political suicide.
Is the system likely to change?
While there are numerous problems with the Electoral College system, the short answer is no. "The Electoral College in theory gives a great advantage to smaller states, because they are over-represented," Dr Hart said. "Small states have an advantage they're reluctant to give up."
In order to change it, however, a two-thirds majority in both the House of Representative and the Senate is required to amend the Constitution. Even if that does succeed, it would need to be ratified by three-quarters of all states.
"There is a political stalemate when it comes to calls to reform it," Dr Hart said.