US Election polls 2020: Biden is still on course to win, but not much needs to change for Trump to gain the advantage

In a strange election, Biden’s comfortable lead could disappear much quicker than you might expect

It’s an unusual election year in the US, and even when leaving aside the pandemic, the two oldest candidates in history, and the sheer fact of the Trump presidency, it’s also a very unusual – and hard to understand – election.

There are two main reasons for that. The first is that Donald Trump has a sizeable electoral college advantage, so just like in 2016 he could lose the popular vote by millions and still capture the presidency again.

The second is that Joe Biden currently has a significant enough lead that if nothing changes, even a systemic polling error can’t bring about a Trump presidency. The problem for Mr Biden is that if his lead is whittled down just a little bit, he’s suddenly in range of a polling error that could mean Mr Trump can wrangle an improbable electoral college victory again.

Biden needs a big lead to take those crucial states

Right now, Biden has somewhere between a 6 and 8 point lead nationally. Most quality polls over the past month have put his lead in that region, with a few higher than that, and some lower quality polls finding a range of results from a +12 Biden lead to a +3 Biden lead.

The i polling average, above, shows there hasn’t been much closing of the gap in the last few weeks, assessing the gap at +6.5 points in favour of Biden. However, as we saw in 2016, that more than six point lead doesn’t actually mean Biden’s lead is six points. Hillary Clinton’s election result was a +2.1 lead – and she lost the election by some way thanks to the whims of the electoral college.

The key states Biden needs

The same is true this year, with Mr Biden needing to win a small number of crucial swing states to capture the electoral college. He has to gain one of either Arizona, Florida or Pennsylvania, while taking back the two previously Democratic states of Minnesota and Wisconsin (though swings to either side could mean many more states come into play). Some other states are also intermittently close according to state polls, including Iowa and Georgia, but they seem less likely to actually swing.

Mr Biden’s lead in those key five states is much less than his national lead. That means if Biden’s national lead drops just a point or two, it’s unlikely he can win Arizona. In Florida, the polling average puts his lead at only around 2 points. So with just a +4.5 Biden lead nationally, Florida is no longer a likely Biden state, and is instead a toss-up between the two candidates.

Wisconsin, Minnesota and Pennsylvania all favour Mr Biden by less than 6 points. To be favoured in those three crucial states, and therefore nationally, Mr Biden will probably need a 2-3 point lead, maybe as high as +3.5. The current +6.5 Biden lead is therefore effectively a 3-4 point lead – and quite possibly less.

Error margins mean slight leads are less comfortable than they look

The reality is that the polls probably won’t be on the money. Polling averages mitigate this to an extent, but generally when looking at polling averages we need to consider the possibility of a three point swing in either direction.

That means we need to consider that uncertainty when looking at the Biden lead. That +6.5 lead, when considering the in-built Trump advantage and the margin of error, is probably between around a 3-4 point lead. If Mr Biden’s lead drops just a few points, the likelihood of a very close election rises rapidly.

In short, at +5 points Biden supporters should be worried. At +2, Trump supporters should be optimistic. Mr Biden doesn’t have a +6.5 lead to play with – he barely has 2 points of room.

The race does remain stable

However, many have spent the last week or two looking for signs that the polls are suddenly closing and Trump is catching up. But there isn’t much evidence that’s happening. In fact, the race is really quite stable.

Since the start of June, the most frequent pollsters have found a wide range of leads for Mr Biden, from 5 points to 14 points. All those results would likely mean a comfortable Biden victory, though at the lower end the margin of error is just about big enough to allow a Trump victory in the electoral college.

But those pollsters don’t consistently agree on a direction of travel. When one is up, another is down, meaning the changes are most likely to be either temporary or due to sampling changes. The average proves this, with the lead staying pretty solid between 6 and 8 points over the last months or so.

It doesn’t mean the Biden lead is safe, of course, as a lot could change. It just means that right now, not a lot has.