A central predicament of the Biden campaign is how to persuade voters to abandon Donald Trump.

“In 2012 the Obama campaign turned a nice guy, Mitt Romney, into a piece of crap,” Steve Murphy, a co-founder of the Democratic media firm MVAR Media, told me. “You can’t do that to Trump because everybody already knows he’s a piece of crap.”

Not only do voters know that Trump is corrupt, a liar, narcissistic and venal, his supporters have repeatedly found ways to slide by his liabilities.

In April, before the former president was convicted on 34 felony counts by a New York jury, and again earlier this month, after he was found guilty, YouGov asked voters:

“Do you think someone who has been convicted of a felony should be allowed to become president?”

In April, before the verdict, Republicans were decisively opposed to a felon becoming president, 17 percent in favor, 58 percent opposed (the remaining 25 percent not sure).

In June, after the conviction, Republicans somersaulted: 58 percent said a felon should be allowed to become president, 23 percent were opposed, and 19 percent were unsure.

YouGov also asked voters: “Do you consider falsifying business records to conceal hush money payments to a porn star a serious crime?”

In six pre-conviction polls from June 2023 to April 2024, the share of Republicans saying it was a serious crime to falsify records was consistently in the 27-to-29 percent range. In June, after Trump’s conviction, the Republican percentage fell to 9 percent.