In just over seven weeks on November 3, the United States will hold its presidential election, alongside an election for the House of Representatives and one third of the Senate. This post will analyse the presidential polls and what they can tell us about Donald Trump and Joe Biden’s prospects for victory.
Unlike in Australia over the last year, there are new polls almost every day in the United States and there are a number of poll aggregators, including FiveThirtyEight’s weighted polling average. FiveThirtyEights’s polling average will be the main source of polling information for this post.
The national picture
As of Sunday, Biden leads FiveThirtyEight’s polling average by 7.6 points. This lead has been extremely steady all year. In fact, since Biden became the de facto Democratic nominee for president after Bernie Sanders suspended his campaign in April, Biden’s lead in the polls over Trump has never dropped below five points.
Since June 5th, Biden’s lead over Trump has not varied by more than a few points, staying above 7 points and below 10 points. That is a very resilient lead and is particularly impressive considering all that has happened in the US over the last five months (read here in case you’ve forgotten).
If Biden wins the popular vote count on election day by his current 7.6 point margin, he will almost certainly be elected president in November.
But, as anyone who followed the 2016 election will remember, winning the popular vote does not guarantee an election victory. Hillary Clinton won the popular vote by 2.1% in 2016, yet failed to win the presidency.
US presidential elections are not determined by winning the national popular vote. Victory requires winning a majority of delegates in the electoral college. Each state is accorded electoral college delegates (from here on called ‘electoral votes’) roughly based on their population, with each state awarded a minimum of three votes (it’s slightly more complicated than that but that’s the short explanation). The most populous state, California, has 55 electoral votes. The District of Columbia, which is not a state, is also awarded three electoral votes.
There are 538 electoral votes in total, so getting a majority requires winning 270 electoral votes.
In 48 states and DC, electoral votes are awarded to the candidate who wins the most votes statewide. In two states, Maine and Nebraska, delegates are awarded a bit differently. Maine awards two electoral votes to the statewide winner and two votes to the winner in each congressional district. Nebraska awards two votes to the statewide winner and three votes to the winner in each district. In 2020, only one electoral vote is likely to be competitive in each of these two states, so I won’t say anything more about them in this post.
The majority of states (and therefore electoral votes) are not competitive at most elections. For example, there are 14 states that have voted Democratic at every presidential election since 1992 and 13 states that have voted Republican at every election since 1980. A further eight states have voted Republican at every election since 2000. The vast majority of these 35 states are not expected to be competitive this year (with a few exceptions that will be discussed below).
So to summarise, becoming president requires a candidate to gain a majority of electoral votes by winning in competitive states.
With the explanation done, let’s turn to the state polls.
Biden is currently leading in the polls in every state that Clinton won in 2016, plus six states that Trump won in 2016.
At the moment, the traditionally competitive states (called ‘swing states’) can be divided into three general groups:
- Swing states where Biden or Trump lead by less than five points. These states are very competitive.
- Swing states where Biden leads by between five and ten points. Biden is the favourite in these states, but they remain competitive.
- Swing states where Biden leads by more than ten points. These states are unlikely to be competitive this year.
Let’s tackle each of these groups in reverse order.
I will also briefly look at the states where Trump is leading by between five and ten points.
Swing states where Biden leads by more than 10 points:
- New Mexico: 13 points
- Maine*: 11 points
- Virginia: 10.8 points
- Colorado: 10.6 points
New Mexico, Virginia and Colorado all voted for Clinton in 2016. These are states that have traditionally been competitive swing states but have been trending more Democratic in recent years. Neither Colorado nor Virginia has been won by a Republican since 2004 and New Mexico has only gone Republican once since 1992. Nonetheless, when Republicans are doing well, they can expect to be competitive in these states.
Clearly that is not the case this year. With Trump underwater nationally by more than 7 points, these states are highly likely to be won by Biden.
Swing states where Biden leads by 5 to 10 points:
- Michigan: 7.6 points
- Minnesota: 7.4 points
- New Hampshire: 6.9 points
- Wisconsin: 6.5 points
- Nevada: 5.9 points
- Pennsylvania: 5.1 points
- Arizona: 5 points
These are seven states where Biden has a decent but not overwhelming lead. Three of these are Democratic leaning swing states that Clinton won in 2016: Minnesota, New Hampshire and Nevada.
Since 1992, New Hampshire has only backed a Republican once and Nevada twice. Minnesota has historically been a safe Democratic state – in fact, it is the only state to have backed a Democrat at every election for the last forty years – but it has been edging to the right over the last decade. Biden’s leads in these states are pretty strong but not overwhelming. If Trump is going to gain any states that Clinton won in 2016, it will be one of these three states.
Biden is also leading in four states that Trump won in 2016: Arizona, and the infamous trio of mid-western states that unexpectedly delivered the presidency to Trump: Michigan, Wisconsin and Pennsylvania.
Until 2016, Michigan and Pennsylvania hadn’t voted for a Republican since 1988 and Wisconsin hadn’t since 1984. But they have been slowing trending to the right and Trump ended up winning all three states in 2016 – each by less than 1%. Had Clinton won these three states, she would have won enough electoral votes to become president. All three states loom as crucial pick-ups for Biden and crucial holds for Trump in 2020.
Arizona is a traditionally Republican state – it has been won by Democrats just once in the last forty years. But it has been shifting to the left over the last decade and this year it may finally cross the threshold.
If Biden can hold New Hampshire, Nevada and Minnesota, while gaining three out of four of Michigan, Wisconsin, Pennsylvania and Arizona, Biden will win the presidency. There is still enough time that Biden’s lead could narrow in all these states by election day and a sizeable polling error may mean that these states are closer than they appear. But you’d much rather be in Biden’s position in these states than Trump’s.
Part two of this post will be posted tomorrow.
All poll numbers used in this post were sourced from 538’s presidential polling averages on Sunday 13thSeptember.
For an overview of each state’s voting history in presidential elections, see here.
To see an interactive map of which states Biden and Trump need to win the presidency, check out 270towin.com.
For a cool visualization of how the partisanship of swing states has changed over the last 20 years, see this 538 article.