Donald Trump's Post-COVID Poll Slump May Be Too Deep for Even a James Comey-Style Intervention

Former Vice President Joe Biden enjoys a commanding poll lead over President Donald Trump with just 27 days before the presidential election on November 3. The president's positive test for COVID-19 doesn't appear to have helped his standing.

However, former Secretary of State Hillary Clinton was also ahead of Trump at this point in the 2016 race but went on to lose the electoral college vote as Trump won narrow victories in Pennsylvania, Michigan and Wisconsin.

On October 28, 2016 then FBI Director James Comey sent a letter to the House Judiciary Committee about the discovery of emails that may have been of importance to the agency's closed investigation of Clinton. Another letter on November 6 exonerated her but many commentators and analysts believe Comey's "October Surprise" swung the election in Trump's favor.

October was a key month during the last presidential election. On October 7, the Access Hollywood tape was released. It showed Trump saying vulgar things about women and quickly became a major campaign issue.

Clinton gained from the controversy, enjoying a poll swing of slightly less than 3 percent. From a lead of 4.6 percent the day the tape was released, she hit a maximum of 7.6 percent before her lead began dropping again.

By comparison, Trump's positive COVID-19 test appears to have had a much more profound effect on his re-election chances. Trump announced he had the virus on Friday, October 2.

A CNN poll conducted by SSRS, which took place from October 1-4, mostly after Trump's diagnosis, shows Biden with a 16-point lead on the president. This is his widest margin yet, though the poll may be an outlier. A Reuters/IPSOS poll from September 29 had Biden up 9 points.

A post-diagnosis poll by ABC News found that 72 percent of respondents didn't think Trump take the "risk of contracting the virus seriously enough" or take "the appropriate precautions when it came to his personal health."

Other recent polls also show Biden ahead nationally, and crucially, he's ahead in key swing states that Trump carried in 2016. Biden leads by 5.9 percent in Michigan, 6.2 percent in Pennsylvania and 6.1 percent in Wisconsin, according to USA Today's average of averages.

Could a James Comey-style event in 2020 change voters' minds enough to swing the election to Trump? As FiveThirtyEight's Nate Silver noted in 2016, Comey's letter accompanied "a swing of about 3 points against her [Clinton]."

RealClearPolitics' polling average has Biden up 9 points against Trump as of October 5, meaning a 3-point swing would still allow him to maintain a 6-point lead over the president. Clinton's average lead was just 3.2 points up to November 7, 2016—the day before the election.

If the CNN/SSRS poll is accurate, even a 3-point shift before the November election wouldn't change the outcome of the race nationally, though it may affect tight races in swing states.

As Vox noted in 2017, polling failed to take into account the "Comey Effect" in battleground states, where a small number of key voters made a last minute switch from Clinton to Trump. A lack of polling in states like Michigan and Wisconsin after the Comey letter contributed to the surprise on election night.

It's worth noting, however, that the CNN/SSRS poll shows 9 in 10 voters have already made up their mind about who they're voting for. Just 8 percent said they might change their preference.

Biden has polled consistently better than Clinton throughout the campaign. A Comey-style intervention causing a 3-point swing would likely not be enough to significantly impact Biden's lead.

More than 3 million ballots have already been cast and 2 million of those were in states CNN rates as "most competitive." Though 130 million votes were cast in 2016, in tight swing state races, ballots already cast could prove crucial.