From “Democratic ad makers think they’ve discovered Trump’s soft spot” by David Siders at Politico:

As in 2016, ad makers are focusing on Trump’s character. But unlike four years ago, they are no longer focusing on his character in isolation — rather they are pouring tens of millions of dollars into ads yoking his behavior to substantive policy issues surrounding the coronavirus, the economy and the civil unrest since the death of George Floyd.

“You can’t chase the Trump clown car,” said Bradley Beychok, president of the progressive group American Bridge. “Him drinking water and throwing a glass is goofy and may make for a good meme, but it doesn’t matter in the scheme of things … What people care about is this outbreak.”

Siders notes that “In their preparations for 2020, outside Democratic groups spent more than a year surveying voters in swing states by phone and online. They convened in-person focus groups and enlisted voters in swing states to keep diaries of their media consumption…Multiple outside groups said they began to test their ads more rigorously than in 2016, using online panels to determine how likely an ad was to either change a viewer’s impression of Trump or to change how he or she planned to vote.”

In addition, “Priorities USA, a major Democratic super PAC, alone expects to test more than 500 ads this cycle. Priorities, American Bridge and other outside groups, including organized labor, have been meeting regularly to share internal research and media plans.”

Among research findings, Siders reports:

The advertising elements that appear to work, according to interviews with more than a dozen Democrats involved in message research, vary from ad to ad. Using Trump’s own words against him often tests well, as do charts and other graphics, which serve to highlight Trump’s distaste for science. Voters who swung from President Barack Obama to Trump in 2016 — and who regret it — are good messengers. And so is Joe Biden, whose voice is widely considered preferable to that of a professional narrator. Not only does he convey empathy, according to Democrats inside and outside Biden’s campaign, but using Biden’s voice “helps people think about him as president,” said Patrick Bonsignore, Biden’s director of paid media.

Siders concludes, “But the ad makers’ overarching takeaway from their research was this: While Trump may not be vulnerable on issues of character alone, as he demonstrated in 2016, he is vulnerable when character is tied to his policy record on the economy and health care.”