The result of the 2024 US presidential election lies in the hands of just seven states: Arizona, Georgia, Michigan, Nevada, North Carolina, Pennsylvania, and Wisconsin. These are considered swing states because the margins between whether they will vote Democratic or Republican are very narrow, meaning they could swing either way.

In order to understand why this matters, however, one must first understand how American presidential elections work.

After fighting the American Revolution to gain representation and independence from Great Britain, the founding fathers aimed to create a central government that would unite the thirteen colonies. At the same time, they wanted to ensure that the people felt represented in this new system of governance.

As a compromise, they established the electoral college, a system designed to balance the influence of the populace with the need for a more stable and controlled electoral process. While the term ‘electoral college’ never appears in the Constitution, article ll, section 1, clauses 2 and 3 explain the system.

How the electoral college works

Each state has the same number of electoral votes as members of Congress: one for each member in the House of Representatives (which is proportional to the population of the state) plus two for the Senate (every state has two senators). For example, California, the most populous state with almost 40 million people, has 54 electoral votes, while Alaska (under 800,000 people) has just three. There are 538 electoral votes in total; in order to win the election, a candidate must win 270 votes.

More often than not, the successful candidate wins both the popular vote and the electoral vote: out of the 58 elections in US history, only in five elections has the winner not won the popular vote. This happened most recently in 2016, when the Democratic nominee Hillary Clinton won the popular vote, but lost the election to Republican nominee Donald Trump because he had amassed 304 electoral votes.

In 2020, 89% of Democrats and 23% of Republicans (which constitutes 61% of Americans), said they would prefer the Constitution to be amended so that the popular vote winner gets to be president.

However, the electoral college system is not likely to change any time soon. Amending the Constitution requires support from two-thirds of both the House of Representatives and the Senate, as well as agreement from 38 out of 50 US states. Yet, given the current polarisation within the United States, a bipartisan agreement to amend the system is very unlikely.

It looks as if the electoral college will again play a crucial role in next week’s result. States that are historically considered blue (Democratic) should earn Kamala Harris 226 points, while states that are considered red (Republican) should earn Donald Trump 219 points. Because that means neither candidate has 270 points, the remaining seven states will determine who is the next US president.

Together these seven states have 93 electoral votes: Pennsylvania (19), Georgia (16), North Carolina (16), Arizona (11), Michigan (15), Wisconsin (10) and Nevada (6).

Projections for the swing states

On October 20, Decision Desk HQ polls published in The Hill showed the following projections, with Trump taking the lead for the first time since Kamala Harris took over from Joe Biden as the Democratic nominee.

Pennsylvania: Trump has approximately a 52% chance of winning Pennsylvania. Pennsylvania is considered one, if not the most, important of the battleground states, as it brings the most electoral votes – 19. Trump won the state by 0.7% in 2016, but lost it in 2020 when Biden won by 1.2%.

Georgia: Trump has a 62% chance of winning Georgia. However, because cities tend to vote Democratic, the Atlanta metro area has caused the state to change from a reliably red state to a state that Biden won in 2020, albeit by just 0.23%.

North Carolina: Trump has a 66% chance of winning North Carolina. He won the state in both 2020 (by about 1.3%) and in 2016 (by 3.8%). Nevertheless, in the past six elections, North Carolina was decided by a margin of less than 6%.

Arizona: Trump has about a 58% chance of winning Arizona. The state has been reliably red for a very long time, starting in 1952 with Dwight D. Eisenhower. In 2020, Biden broke this 68-year streak, winning by a small margin: 0.3%. The Phoenix metro area, holding about two-thirds of Arizona’s population, follows the trend of urban areas, being majority blue and was big for the Democrats in 2020, but as of now, Trump is projected to win in Arizona.

Michigan: Harris has a 58% chance of winning Michigan. The state voted Democrat in every presidential election from 1992 to 2012, until Donald Trump secured the win in 2016, beating Hillary Clinton by just 0.2%. A shift back to blue occurred in 2020 when Biden won by 2.8%.

Wisconsin: Trump has a 53% chance of winning Wisconsin. He won Wisconsin before in 2016 by just 0.77%, but Joe Biden was able to turn the state blue in 2020. Although the state is considered part of the “blue wall,” the margins in 2000, 2004, 2016 and 2020 were all less than 1%. The only exceptions to this trend occurred in 2008 and 2012, when Barack Obama won by larger margins.

Nevada: Harris has a 52% chance of winning Nevada. While Nevada has not been Republican since George W. Bush in 2004, it has slowly been shifting right. In fact, the national popular vote has shifted left, but Nevada has moved about 2.5 points to the right relative to the national average. So, while Harris is currently predicted to win here, the rightwards shift makes it a close call.

Who will win?

If each of the swing state polls listed above are correct about what happens on November 5, then Kamala Harris would gain 247 electoral votes and Donald Trump 291 votes, meaning that he would win the election and become the 47th president of the United States

However, one must keep in mind that polls are not always right (and can change right up until election day). National polls currently suggest that Harris is leading by a slight margin, 2 percentage points – 49% to 47%.

In 2016, polls estimated that Democratic candidate Hillary Clinton had a 90% chance of beating Donald Trump, but Trump still ended up winning. Among the reasons for the incorrect polls were that some voters were shy to support Trump in polls because of his controversial rhetoric during his campaign. Also, non-college-educated voters, many of whom supported Trump, were underrepresented in the polls because college-educated people, many of whom supported Clinton, are more likely to respond to polls.

For the 2024 election, pollsters have been trying to construct more accurate polls by weighing aspects such as gender, age, race, income, and, especially, education. Because of the margin of error (typically ±3% to ±5%), one should never look at polls as fact, but rather to see trends.

Some experts insist that the election is still a toss-up. Others say it is the closest presidential election for almost 150 years – the last one with numbers like this was way back in 1876.

So, while currently Donald Trump is projected to win by a small margin, according to the swing state polls, it is impossible to know how the electoral college system will make things turn out until all the votes are counted and a winner is clear.