Republican president is being challenged by Democratic Party nominee Joe Biden, who is best known as Barack Obama’s vice-president but has been in US politics since the 1970s.
Voters in America will decide on 3 November whether Donald Trump remains in the White House for another four years.
As election day approaches, polling companies will be trying to gauge the mood of the nation by asking voters which candidate they prefer.
We’ll be keeping track of those polls here and trying to work out what they can and can’t tell us about who will win the election.
Biden leading national presidential polls
National polls are a good guide as to how popular a candidate is across the country as a whole, but they’re not necessarily a good way to predict the result of the election.
In 2016, for example, Hillary Clinton led in the polls and won nearly three million more votes than Donald Trump, but she still lost – that’s because the US uses an electoral college system, so winning the most votes doesn’t always win you the election.
With that caveat aside, Joe Biden has been ahead of Donald Trump in most national polls since the start of the year. He has hovered around 50% in recent months and has had a 10-point lead on occasions.
Who’s ahead in national polls?
DEMOCRAT
BIDEN
52%
REPUBLICAN
TRUMP
44%
Trend line showing average voting intention based o
average voting intention based on individual polls
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Date
BIDEN
TRUMP
Nov 02
52
44
Nov 02
52
44
Nov 01
52
44
Nov 01
52
44
Nov 01
52
44
Nov 01
52
44
Nov 01
52
44
Oct 31
52
44
Oct 31
52
44
Oct 31
52
44
Oct 31
52
44
Oct 31
52
44
Oct 30
52
43
Oct 30
52
43
Oct 29
52
43
Oct 29
52
43
Oct 29
52
43
Oct 29
52
43
Oct 28
52
43
Oct 28
52
43
Oct 28
52
43
Oct 28
52
43
Oct 28
52
43
Oct 27
51
42
Oct 27
51
42
Oct 27
51
42
Oct 27
51
42
Oct 27
51
42
Oct 27
51
42
Oct 26
51
43
Oct 26
51
43
Oct 26
51
43
Oct 26
51
43
Oct 26
51
43
Oct 25
51
42
Oct 25
51
42
Oct 25
51
42
Oct 24
51
43
Oct 24
51
43
Oct 24
51
43
Oct 24
51
43
Oct 23
51
42
Oct 23
51
42
Oct 22
51
43
Oct 22
51
43
Oct 21
51
43
Oct 21
51
43
Oct 20
51
43
Oct 20
51
43
Oct 20
51
43
Oct 20
51
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Oct 20
51
43
Oct 19
52
42
Oct 19
52
42
Oct 19
52
42
Oct 19
52
42
Oct 18
52
42
Oct 18
52
42
Oct 18
52
42
Oct 18
52
42
Oct 17
52
42
Oct 17
52
42
Oct 17
52
42
Oct 16
52
42
Oct 16
52
42
Oct 15
52
42
Oct 15
52
42
Oct 15
52
42
Oct 14
52
42
Oct 14
52
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Oct 13
53
42
Oct 13
53
42
Oct 13
53
42
Oct 13
53
42
Oct 13
53
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Oct 13
53
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Oct 13
53
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Oct 12
52
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Oct 12
52
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Oct 12
52
42
Oct 12
52
42
Oct 11
53
42
Oct 11
53
42
Oct 10
52
42
Oct 10
52
42
Oct 09
52
42
Oct 09
52
42
Oct 08
52
42
Oct 07
52
42
Oct 06
52
42
Oct 06
52
42
Oct 06
52
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Oct 06
52
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Oct 06
52
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Oct 06
52
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Oct 05
51
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Oct 04
51
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Oct 04
51
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Oct 04
51
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Oct 04
51
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Oct 03
51
43
Oct 03
51
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Oct 02
51
42
Oct 01
51
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Oct 01
51
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Oct 01
51
43
Oct 01
51
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Sep 30
51
43
Sep 30
51
43
Sep 30
51
43
Sep 29
51
43
Sep 29
51
43
Sep 29
51
43
Sep 28
50
43
Sep 27
50
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Sep 27
50
43
Sep 26
50
43
Sep 25
50
43
Sep 25
50
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Sep 24
50
43
Sep 24
50
43
Sep 24
50
43
Sep 23
51
43
Sep 23
51
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Sep 22
51
43
Sep 22
51
43
Sep 22
51
43
Sep 22
51
43
Sep 21
51
43
Sep 21
51
43
Sep 21
51
43
Sep 20
51
43
Sep 20
51
43
Sep 19
51
43
Sep 19
51
43
Sep 19
51
43
Sep 18
50
43
Sep 17
51
43
Sep 16
51
43
Sep 16
51
43
Sep 16
51
43
Sep 15
50
43
Sep 15
50
43
Sep 15
50
43
Sep 15
50
43
Sep 14
51
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Sep 14
51
43
Sep 13
51
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Sep 12
51
43
Sep 12
51
43
Sep 11
51
43
Sep 10
51
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Sep 10
51
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Sep 09
51
43
Sep 08
51
43
Sep 08
51
43
Sep 08
51
43
Sep 08
51
43
Sep 08
51
43
Sep 08
51
43
Sep 07
50
42
Sep 06
50
42
Sep 06
50
42
Sep 05
51
43
Sep 04
51
42
Sep 04
51
42
Sep 03
51
42
Sep 02
51
43
Sep 02
51
43
Sep 01
50
42
Sep 01
50
42
Sep 01
50
42
Sep 01
50
42
Sep 01
50
42
Sep 01
50
42
Aug 31
50
42
Aug 31
50
42
Aug 31
50
42
Aug 31
50
42
Aug 31
50
42
Aug 30
50
41
Aug 30
50
41
Aug 29
51
42
Aug 28
51
43
Aug 28
51
43
Aug 27
51
43
Aug 26
50
43
Aug 25
50
42
Aug 25
50
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Aug 25
50
42
Aug 24
50
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Aug 23
50
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Aug 22
50
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Aug 21
50
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Aug 20
50
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Aug 19
50
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Aug 18
50
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Aug 18
50
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Aug 18
50
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Aug 17
50
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Aug 16
50
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Aug 15
50
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Aug 15
50
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Aug 14
50
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Aug 14
50
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Aug 13
50
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Aug 12
50
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Aug 12
50
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Aug 11
50
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Aug 11
50
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Aug 11
50
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Aug 11
50
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Aug 10
50
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Aug 09
49
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Aug 08
49
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Aug 07
49
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Aug 06
50
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Aug 05
50
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Aug 04
50
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Aug 04
50
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Aug 03
50
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Aug 02
50
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Aug 01
50
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Jul 31
50
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Jul 30
50
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Jul 29
49
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Jul 28
49
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Jul 28
49
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Jul 28
49
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Jul 27
50
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Jul 26
51
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Jul 25
51
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Jul 24
51
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Jul 23
51
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Jul 22
50
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Jul 21
50
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Jul 21
50
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Jul 20
50
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Jul 19
51
41
Jul 18
51
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Jul 17
50
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Jul 16
50
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Jul 15
50
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Jul 15
50
41
Jul 14
50
40
Jul 14
50
40
Jul 13
51
40
Jul 12
51
40
Jul 12
51
40
Jul 11
49
40
Jul 10
49
40
Jul 09
49
40
Jul 08
49
40
Jul 07
50
41
Jul 07
50
41
Jul 06
49
41
Jul 05
49
40
Jul 04
49
40
Jul 03
49
40
Jul 02
49
40
Jul 01
50
41
Jun 30
50
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Jun 30
50
41
Jun 30
50
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Jun 29
50
41
Jun 28
49
41
Jun 27
50
40
Jun 26
50
40
Jun 25
50
41
Jun 24
50
41
Jun 23
50
40
Jun 23
50
40
Jun 22
50
41
Jun 22
50
41
Jun 21
50
41
Jun 20
50
41
Jun 19
50
41
Jun 18
51
41
Jun 17
50
41
Jun 16
50
41
Jun 16
50
41
Jun 15
49
41
Jun 14
50
42
Jun 13
49
41
Jun 12
49
41
Jun 11
49
42
Jun 10
49
42
Jun 09
49
42
Jun 08
49
42
Jun 07
49
42
Jun 06
49
42
Jun 05
49
42
Jun 04
49
42
Jun 03
49
42
Jun 03
49
42
Jun 03
49
42
Jun 02
48
41
Jun 02
48
41
Jun 01
48
42
Jun 01
48
42
May 31
48
42
May 30
48
43
May 29
48
43
May 28
48
43
May 27
48
42
May 26
48
42
May 25
48
42
May 24
48
42
May 23
48
43
May 22
48
43
May 21
48
43
May 20
48
43
May 19
48
43
May 19
48
43
May 18
49
44
May 17
49
44
May 16
49
44
May 15
49
44
May 14
49
43
May 14
49
43
May 13
48
43
May 12
47
43
May 11
48
43
May 10
48
43
May 09
47
42
May 08
48
42
May 07
48
42
May 06
48
42
May 05
48
42
May 04
48
42
May 03
47
42
May 02
48
42
May 01
48
42
Apr 30
48
42
Apr 29
48
42
Apr 28
48
42
Apr 28
48
42
Apr 27
49
42
Apr 26
49
42
Apr 25
49
42
Apr 24
48
42
Apr 23
48
42
Apr 22
48
42
Apr 21
48
42
Apr 20
48
43
Apr 19
49
43
Apr 18
49
43
Apr 17
49
42
Apr 16
49
42
Apr 15
48
42
Apr 14
48
42
Apr 13
48
42
Apr 12
48
42
Apr 11
48
42
Apr 10
48
42
Apr 09
48
42
Apr 08
48
42
Apr 07
48
42
Apr 07
48
42
Apr 07
48
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Apr 06
49
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Apr 06
49
42
Apr 06
49
42
Apr 05
48
43
Apr 04
48
43
Apr 03
48
43
Apr 02
48
43
Apr 01
49
44
Mar 31
49
45
Mar 30
49
45
Mar 29
49
45
Mar 28
49
45
Mar 27
49
45
Mar 26
49
45
Mar 25
49
44
Mar 24
49
43
Mar 24
49
43
Mar 23
50
44
Mar 22
50
44
Mar 21
52
42
Mar 20
52
43
Mar 19
52
43
Mar 18
52
42
Mar 17
52
42
Mar 16
52
43
Mar 15
52
43
Mar 14
52
43
Mar 13
52
43
Mar 12
52
43
Mar 11
51
43
Mar 10
50
43
Mar 09
51
42
Mar 08
51
42
Mar 07
50
43
Mar 06
49
45
Mar 05
49
45
Mar 04
49
45
Mar 03
49
45
Mar 02
49
45
Mar 01
50
45
Feb 29
50
45
Feb 28
50
45
Feb 27
50
44
Feb 26
50
45
Feb 25
50
45
Feb 24
50
45
Feb 23
50
45
Feb 22
50
45
Feb 21
50
44
Feb 20
50
44
Feb 19
50
44
Feb 18
50
44
Feb 17
51
44
Feb 17
51
44
Feb 16
50
44
Feb 15
50
43
Feb 14
50
43
Feb 13
50
43
Feb 12
50
46
Feb 11
50
44
Feb 10
50
44
Feb 09
50
44
Feb 08
49
44
Feb 07
49
44
Feb 06
49
44
Feb 05
50
46
Feb 04
50
45
Feb 03
50
45
Feb 02
50
45
Feb 01
50
44
Jan 31
50
44
Jan 30
50
44
Jan 29
50
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Jan 28
50
44
Jan 27
50
45
Jan 26
50
45
Jan 25
50
45
Jan 24
50
46
Jan 23
50
46
Jan 23
50
46
Jan 22
50
44
Jan 21
51
45
Jan 20
51
45
Jan 19
51
45
Jan 18
48
46
Jan 17
48
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Jan 16
48
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Jan 15
48
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Jan 14
48
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Jan 13
48
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Jan 12
48
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Jan 11
48
46
30 days until Election day
The BBC poll of polls looks at the individual national polls from the last 14 days and creates trend lines using the median value, i.e. the value in the middle of the set of numbers.
See individual polls
By contrast, in 2016 the polls were far less clear and just a couple of percentage points separated Mr Trump and his rival in the days before the election.
Which states will decide this election?
As Mrs Clinton discovered in 2016, the number of votes you win is less important than where you win them.
Most states nearly always vote the same way, meaning that in reality there are just a handful of states where both candidates stand a chance of winning. These are the places where the election will be won and lost and are known as battleground states.
In the electoral college system the US uses to elect its president, each state is given a number of votes based on how many members it sends to Congress – House and Senate. A total of 538 electoral college votes are up for grabs, so a candidate needs to hit 270 to win.
As the map above shows, some battleground states have a lot more electoral college votes on offer than others so candidates often spend a lot more time campaigning in them.
Who’s leading in the battleground states?
At the moment, polls in the battleground states look good for Joe Biden – although the margins have tightened in recent days.
Mr Biden appears to have decent leads in Michigan, Pennsylvania and Wisconsin – three industrial states his Republican rival won by margins of less than 1% to clinch victory in 2016.
Latest polling averages in battleground states
Click a column header to sort the table by that column in ascending or descending order
Arizona
47.9%
47.0%
Trump by 3.6%
Florida
47.9%
47.0%
Trump by 1.2%
Georgia
47.2%
48.2%
Trump by 5.2%
Iowa
45.6%
47.6%
Trump by 9.5%
Michigan
50.0%
45.8%
Trump by 0.2%
Minnesota
48.0%
43.7%
Clinton by 1.5%
Nevada
47.5%
45.3%
Clinton by 2.4%
New Hampshire
53.4%
42.4%
Clinton by 0.4%
North Carolina
47.6%
47.8%
Trump by 3.7%
Ohio
46.0%
47.4%
Trump by 8.2%
Pennsylvania
48.7%
47.5%
Trump by 0.7%
Texas
46.5%
47.7%
Trump by 9.1%
Virginia
51.7%
40.3%
Clinton by 5.4%
Wisconsin
51.0%
44.3%
Trump by 0.8%
Source: Real Clear Politics, Associated Press. Last updated: 3 November
But it’s the battleground states where Mr Trump won big in 2016 that his campaign team will be most worried about. His winning margin in Iowa, Ohio and Texas was between 8-10% back then but it’s currently looking much closer in all three.
That’s one of the reasons why some political analysts rate his chances of re-election as low as things stand.
The Economist thinks Mr Biden is “very likely” to beat Mr Trump while FiveThirtyEight, a political analysis website, sees Mr Biden as “favoured” to win the election but says the president could still come out on top.
Who won the presidential debates?
Donald Trump and Joe Biden went head-to-head in two live TV debates.
The first, on 29 September, was a chaotic affair, with Mr Trump’s combative approach stamping out any chance of a real debate.
A CBS News/YouGov poll taken straight afterwards suggested it was a good night for Mr Biden.
Of those who watched, 48% said Mr Biden was the winner while 41% went for Mr Trump – a similar split to national polling averages. Nearly 70% of people said the debate made them feel “annoyed”.
In the second debate, on 22 October, organisers introduced a mute button to help police the arguments.
But it was a much more restrained President Trump on show and there was a much greater focus on the policies of the two candidates.
While that seemed to help Mr Trump somewhat, snap polls still suggested viewers thought Mr Biden’s performance was more impressive.
A CNN poll found 53% of viewers thought the Democrat had done a better job in the debate, while 39% went with Mr Trump.
A YouGov snap poll was similar, with 54% saying Mr Biden had won compared to 35% for the president.
So while Mr Trump put in a better performance, it’s unlikely to have been enough to change the balance of the race on its own.
Has Covid-19 affected Trump’s numbers?
We only had a couple of days to mull over the first debate before President Trump’s bombshell tweet in the early hours of 2 October revealed he and the first lady had tested positive for coronavirus.
While the pandemic has dominated headlines in the US since the start of the year, the focus had shifted to the Supreme Court after the death of long-serving Justice Ruth Bader Ginsburg in September.
So Mr Trump’s positive coronavirus test put his response to the pandemic, which has claimed the lives of more than 230,000 people in the US, back under the spotlight.
According to data from an ABC News/Ipsos poll, just 35% of Americans approve of how the president has handled the crisis. That figure climbs among Republicans, but only to 76%.
On his own health, 72% of respondents said that Mr Trump did not take the “risk of contracting the virus seriously enough,” while the same number said he failed to take “the appropriate precautions when it came to his personal health”.
A similar Yahoo News/YouGov poll found that about half of respondents believed he could have avoided contracting the disease altogether if he had practised greater social distancing and worn a face mask.
It’s easy to dismiss the polls by saying they got it wrong in 2016 and President Trump frequently does exactly that. But it’s not entirely true.
Most national polls did have Hillary Clinton ahead by a few percentage points, but that doesn’t mean they were wrong, since she won three million more votes than her rival.
Pollsters did have some problems in 2016 – notably a failure to properly represent voters without a college degree – meaning Mr Trump’s advantage in some key battleground states wasn’t spotted until late in the race, if at all. Most polling companies have corrected this now.
But this year there’s even more uncertainty than normal due to the coronavirus pandemic and the effect it’s having on both the economy and how people will vote in November, so all polls should be read with some scepticism.