What is the electoral college?

The electoral college is the mechanism by which America elects its president, and it’s unique to the US. In most countries, you either elect a member of parliament democratically and then those members go on to form a government, or there is a popular vote to choose the president. In the US system, the popular vote of each state instead chooses a certain number of electors, and the number of those is calculated by the number of members of Congress and the number of senators in each state. So, if you have a state that has, say, five members of Congress, add in the two senators, and you have seven electoral votes in that State.

This matters because most states in the US pick their electors using a ‘winner-takes-all’ method, so even if a candidate only wins by 1 percent in a particular state, that candidate will win all of its electors. For example, Florida has 29 electoral votes, so if you win that state, even by a tiny margin, you win all 29 of those; it’s not proportional.

On election day, Americans choose their electors, and those electors will typically vote for the candidate who wins that state. Then, later in the year, those electors will come together and vote, and make the results of election day official.

There are two exceptions: Nebraska and Maine choose their electors by congressional district, rather than by the winner-takes-all method, so if Donald Trump takes Nebraska, Joe Biden could still get some electors by winning a congressional district in one of those states, or vice versa.

So, the presidential election is not a popular vote across the country; in fact, in several recent elections — 2000 and 2016 come to mind — the winner did not win the national popular vote.

How many votes are needed to win?

There are 538 electoral votes up for grabs, and you need 270 electoral votes for the win.

Which are the swing states?

The states that we have been watching throughout this year at CNN are Wisconsin, Michigan, North Carolina, Arizona, Pennsylvania and Florida, to which I would also add Ohio. As the year has progressed, we’ve added more to that list: Iowa, Georgia, Nevada and some people even say Texas.

The interesting thing about these battleground states is that, except for Nevada, they are all states that Donald Trump won in 2016. All Joe Biden needs to do in this election is capture the states that Hillary Clinton won, plus three more states, and he will be president. In 2020, Donald Trump will have to defend more states than Joe Biden if he is to win.

These battleground states really fall into two categories. Firstly, you have the so-called Rust Belt states: manufacturing hubs like Michigan, Pennsylvania and Wisconsin. These are states that have traditionally been Democrat states, and they’re states in which Donald Trump defeated Hillary Clinton in 2016.

The second category is comprised of states that have experienced demographic shifts. These states, like Florida, Arizona, Georgia and North Carolina, have seen increasing numbers of Hispanics and, in some areas, African Americans, so the demographic is shifting from a predominantly white population toward a growing minority population. This is leading to political shifts as well: As these states become more diverse, not to mention in some cases younger in profile, that could benefit Joe Biden and the Democrats. They will be hoping that 2020 is the year that some of those states reach a tipping point for Democrats.

In terms of issues, there are always specific ones that motivate certain parts of the electorate. For some evangelical voters, it may be abortion; for other voters, it might be immigration or perhaps gun control.

But in this election, our surveys are showing us that there are two issues overshadowing all others: firstly, the coronavirus disease (COVID-19) crisis and how the President has handled it; and then the economy overall and which candidate is most likely to lead the country back to a strong recovery.

Our surveys suggest that if your number-one issue is COVID-19, then you are more likely to be a Biden voter. If you’re more focused on how best to get the economy back on track, however, then you may be a Trump voter. As we head into the final week, these are really the two key issues across the country. 

When will we know the result?

It is less likely that we will get a result on election night than in other years because more Americans will be voting by mail than in any US election in history.

Put simply, it takes longer to count mail-in votes. There are mechanical things that slow the process. For example, you have to open the envelope (in some states there are two envelopes); most states check signatures against your voter registration card; you have to make sure the registration information matches the ballot and that you have not yet voted.

All that processing takes time. Because of that, and because some states take longer than others to count, we expect that we may not be able to make a projection on election night — but it is still possible. Some states have already started counting mail-in ballots. Florida is one of them; they started the second week of October. 

But even if we don’t get a winner on election night, that’s okay. It doesn’t mean anything is wrong. Remember, in two out of the last five elections we didn’t know the result on election night. In 2000, it famously took 31 days because they had to recount all the Florida ballots. In 2004, the election came down to one state — Ohio — and it wasn’t until noon the next day that we were able to project Ohio for George W. Bush, and he defeated John Kerry.

Everybody needs to be patient and let the states count the votes, open those mail-in ballots, report the votes and we’ll know the winner soon enough. 

Are mail-in ballots fraudulent?

There is no evidence of widespread fraud in mail-in or in-person elections in the US. All sorts of security measures are taken to make sure that people only vote once and that the person who sends in the ballot is the person whose name is on the ballot.

Some states, Republican and Democratic, have had mail-in voting for many years. Utah and Oregon have had almost entirely mail-in ballots for years with no significant evidence of fraud. Mail-in voting frequently has a higher participation rate, so there are some societal benefits in that respect. 

What happens if Trump doesn’t accept the result?

There are paths to legal challenges or recounts in some states if the result is exceptionally close — as we saw in Florida in 2000 — but most elections are not close, so I think the chances are that a clear winner will emerge.

The vote reporting will be carried out in an orderly fashion, and at some point we will project a winner, and states will eventually certify the results. It just might take a few days.

When does the winner move into the White House?

On Jan. 20, at noon, the inauguration takes place. This is written in the constitution. At that moment, if there is a new president, an interesting tradition takes place: When the outgoing president heads to the Capitol for the inauguration, a team of movers comes in and moves his personal belongings out of the White House and brings all the new president’s personal belongings in. You actually see the moving trucks arrive as the dignitaries gather at the Capitol.

After the inauguration, when a new president arrives, all his belongings are in place, his photos are on his desk and everything is ready for him to get to work.

What happens if there is a tie?

That’s highly unlikely, but technically possible. There are a couple kinds of ties. You could have a tie in a state, but that’s next to impossible given the vast numbers of people voting.

A more likely scenario is an electoral college tie, and the constitution has a provision for that: The election is decided in the House of Representatives, with each state casting one vote. Under the current make-up of the House, because the Republicans hold a majority of the delegations, Donald Trump would likely be re-elected in that scenario.

Given their ages, what happens if whoever wins passes away in office?

The vice president takes over, and the new president picks a vice president. This last happened in 1963, when Lyndon B. Johnson took office following John F. Kennedy’s death, and Johnson appointed Hubert Humphrey to serve as vice president.

Are there also elections for Congress?

In 2020, we will elect the entire US House of Representatives — 435 seats — and about a third of the Senate. Senators have six-year terms, so every two years about a third of that chamber is elected. Many states have elections for governors, mayoral races, local elections, and city council races, so a lot of elections will be taking place this year.

Follow the US election on CNN International and at cnn.com/election