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.

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.

This has been a continuing pattern for Trump loyalists.

In 2011, well before Trump’s presidential campaign, P.R.R.I. (formerly the Public Religion Research Institute) asked members of different denominations whether “elected officials can still perform their public duties in an ethical manner even if they have committed immoral personal acts.”

In 2016, when Trump became the Republican nominee, P.R.R.I. posed the same question. This time, 72 percent of white evangelical protestants said a personally immoral politician could conduct himself ethically in public office, the highest percentage for all the denominations queried.

John Ganz, a political analyst and the author of the new book “When the Clock Broke: Con Men, Conspiracists and How America Cracked Up in the Early 1990s,” captures this aspect of Trump in “The Shadow of the Mob: Trump’s Gangster Gemeinschaft,” an essay posted last week on Ganz’s Substack, Unpopular Front.

“So, Donald Trump is now a convicted felon. Will voters mind?” Ganz, who is doubtful, wonders: “Maybe even those who are not the MAGA faithful but view Trump in a more ambivalent way may not be much bothered by Trump’s official status as a criminal. And some might even find something attractive in it.”

How could that be? To answer that question, Ganz writes that Trump

talks and acts like a Mafioso. He’s not trying to hide it. He has compared himself to Al Capone frequently. The New York Times reported last week, “Trump Leans Into an Outlaw Image as His Criminal Trial Concludes.”

Voters drawn to Trump, Ganz argues, believe that the system — the rule of law, liberal democracy, political equality — has failed.

For this constituency,

Trumpism offers the appearance of a solution: Rackets don’t just take care of the material well-being of the insiders, they are always also sources of recognition and belonging. You’re part of the clan, the crew, the family.

Trump, in this context, “speaks to the longing to a return to something earlier, ‘the original closeness of blood,’ something more organic than society: the gang, the mob, la famiglia — to Gemeinschaft.”

Trump represents a shock to the system. His supporters don’t hold him to the same ethical standards. He’s the antihero, the Soprano, the “Breaking Bad,” the guy who does bad things, who is a bad guy but does them on behalf of the people he represents.

Kabir Khanna, deputy director of elections and data analytics for CBS News, emailed me in response to my inquiries concerning the problems facing Democrats who seek to attack Trump.

“Part of the issue for Democrats,” he wrote, “is that views of Trump are pretty well established for most of the electorate. Most people know what they think of him. Perhaps the best an opposition campaign can hope to do is raise the salience of certain issues, policies, or aspects of his leadership style.”

Many voters, Khanna continued, “recall a good economy under Trump’s watch, seemingly discounting the 2020 pandemic-related downturn, and expect their finances to improve in a second Trump term.” This selective memory is particularly important among “less politically engaged voters, many of whom felt things were better prepandemic than now, while being less attuned to his inflammatory rhetoric, legal baggage and specific plans if re-elected.”

One of the major hurdles facing Democrats, according to Khanna, is that Trump’s “likability gap”

is not translating to a lead in vote preferences. That’s because a sizable chunk of voters who don’t like the way Trump handles himself personally are backing him anyway, and it’s primarily to oppose Biden. Among these Trump “dislikers,” 28 percent are currently voting for him or leaning his way. That includes 85 percent of Republicans and 31 percent of independents who dislike him, but only 2 percent of Democrats.

While these voters don’t like the way Trump behaves, Khanna pointed out, they still give him

very high marks on a series of descriptors, including “tough,” “effective,” “energetic,” “focused” and “competent” — each is selected by at least eight in ten, with “compassionate” being the only adjective we tested on which he’s underwater. And eight in ten say he fights for people like them.

Who are these voters who don’t like Trump, but are still planning to vote for him?

Khanna:

They are disproportionately Trump’s female and college-educated backers. They also identify as moderate at higher rates than “likers,” and if they report having voted in a G.O.P. primary, they were somewhat more likely to have backed Nikki Haley or Ron DeSantis (though most cast their ballot for Trump). They are also likelier to describe the charges related to the events of Jan. 6 that Trump tried to overturn after the 2020 election as serious — more so than the payments to a porn star he was found guilty of in New York. Most don’t want Trump to have more presidential power if re-elected, and in contrast to most of his likers, don’t want him to use the criminal justice system to get revenge against his political opponents.

Khanna argued that recent CBS polling shows that

These voters are less firm in their decisions: just half say their support for Trump is “Very strong — I’ve decided.” While very few of them express a willingness to consider Biden, it’s possible some won’t vote for either man this year. They just might reconsider their support if they come to believe that Trump is more focused on revenge and self-preservation than on materially improving Americans’ lives.

The Biden-Harris campaign has spent roughly $64.4 million on media — television, radio and digital ads — through the end of May, according to Federal Election Commission reports and Open Secrets, a nonprofit campaign disclosure site.

The Biden ads have not produced significant changes in polling results, which show a remarkably consistent pattern — a tight race. The most recent RealClearPolitics aggregation of survey data has Trump ahead by 0.5 percent.

The failure of the Biden media onslaught to move the needle so far reflects the fact that Trump’s supporters see his unscrupulous and nefarious character, openly on exhibit, as a strength, not a liability.

Anat Shenker-Osorio, principal and founder of ASO Communications, has been conducting focus groups testing anti-Trump messages and commercials. In an email, she described some of what she and her colleagues have found:

Generally, we find “is” constructions less effective than “will do” ones. When you say, “Trump is …” and then fill in some character details, you’re inviting voters to consider whether you’re “playing politics as usual” and simply being Team Blue impugning Team Red. Focusing on “Trump will do” and filling that in with some concrete, voter-facing, future harm is more effective. And by effective, I mean both edging the conflicted voter away from Trump and motivating the folks who are tuned out into viewing this election as something in which they must participate.

Shenker-Osorio said, however, that there are “two absolutely essential caveats.”

The first is that “we now have a brand-new ‘Trump is …’ ” — felon.

That is a very different moniker than, say, “unhinged,” “only in it for himself,” “racist,” “corrupt” or even “sexual predator.” It’s an appellation born of a decision reached by a jury of everyday Americans, not government officials, and one that packs a potent punch in a culture with a deep interest in all things crime-related. It’s not the opposing party purportedly name-calling Trump but rather an inescapable truth, even for those clueless about or skeptical of the details of the crimes.

The second is that there can even be problems with messages using “Trump will do,” and Shenker-Osorio said it is sometimes more effective to say “ ‘MAGA will do’ ” because “ ‘MAGA will do’ counters skepticism that the agenda will get enacted.”

On the other hand, Shenker-Osario wrote, “Trump’s most potent ads are those that show actual empathy for voters’ lived experiences. They speak to the economic concerns many people are having right now about cost of living and making ends meet blaming Biden for these troubles.”

In “Trump Conviction Shows There’s No 2024 Game Changer Coming,” Ed Kilgore, a former Democratic operative who is now a political columnist for New York magazine, explains from a separate vantage point Trump’s seeming invulnerability:

You can argue all day about why Trump seems to be “Teflon Don” or even conclude that it’s not about him but about his feckless opponents in both parties or about an atmosphere of partisan polarization that nothing can penetrate. But whatever it is, we’re in a presidential contest that appears to be all but impervious to the kinds of things that used to be called “game changers.”

It’s time to accept at least as a rebuttable presumption that the game isn’t changing. And that has implications for future events like the presidential debates, the two major-party conventions, and the cut-and-thrust of the campaign competition as the November election grows nigh.

Trump, Kilgore continues,

is incapable of moderating his savage and vengeful message, and this year’s turnout dynamics could make Biden’s base of support more reliable. And Trump’s polling lead, even though it has induced regular panic in some Democratic ranks, has never been more than a few ticks away from vanishing altogether.

But no one should expect Trump to self-destruct or persuadable voters to wake up some morning and realize what a terrible man he is.

The strategy adopted by Trump and his allies to deal with his apparent liabilities is not to change course, but to double down.

On Jan. 6, Trump posted one of his increasingly typical rants on Truth Social, which has to be read in full to be appreciated:

It is a Total and Complete American Tragedy that the Crooked Joe Biden Department of Injustice is so desperate to jail Steve Bannon, and every other Republican, for that matter, for not SUBMITTING to the Unselect Committee of Political Thugs, made up of all Democrats, and two CRAZED FORMER REPUBLICAN LUNATICS, Cryin’ Adam Kinzinger, and Liz “Out of Her Mind” Cheney. It has been irrefutably proven that it was the Unselects who committed actual crimes when they deleted and destroyed all material evidence, in a pathetic attempt to protect Crazy Nancy Pelosi and other Democrats from the TRUTH — THAT I DID ABSOLUTELY NOTHING WRONG. The un-American Weaponization of our Law Enforcement has reached levels of Illegality never thought possible before. INDICT THE UNSELECT J6 COMMITTEE FOR ILLEGALLY DELETING AND DESTROYING ALL OF THEIR “FINDINGS!” MAGA2024.

Dr. Phil McGraw, a television host sympathetic to Trump, pointedly encouraged him to abandon his threats to prosecute adversaries if re-elected. During an hourlong conversation with Trump last week on “Dr. Phil Primetime,” McGraw said: “There are headlines out there that say, when you win your second term, that you are going to make the people that have come after you pay retribution and revenge.”

McGraw then suggested to Trump that he abandon his threats to prosecute his adversaries:

Let me ask you this, before you even respond to that, I want to play “what if” with you for a minute. What if when you win this election, you said, “Enough is enough? Too much is too much. This is a race to the bottom, and it stops here.”

Trump initially took the bait, telling McGraw “I’m OK with it. I am. I’m OK with that,” but quickly returned to form: “Sometimes revenge can be justified, though. I have to be honest, sometimes it can.”

Trump’s strategy of openly declaring his intentions is “an age-old gambit from the authoritarian playbook,” according to Adam Parkhomenko, a Democratic political strategist, writing in Los Angeles magazine this week.

In “Trump Is Conditioning Americans With Authoritarian Statements,” Parkhomenko describes Trump’s underlying calculation:

Trump, like aspiring authoritarians before him, is fostering a national environment in which his self-first vision of governance can be achieved. He is conditioning and reconditioning Americans to tolerate central tenets of authoritarianism. Sadly, the sinister strategy is thus far working.

Each time he speaks of eroding the norms of American governance, our national and individual alarm bells ring a little quieter than the time before. Numbness permeates about the grave danger he represents.

How does this process of generating tolerance for authoritarianism work?

Evil intentions are floated. Reactions are assessed. Weaknesses are exploited. Intentions are repeated. Wrongs become desensitized. Scapegoats are named. Opposition is divided and conquered. Power is grabbed. Distractions are created. Dissent is squashed. Then, with the groundwork complete, what was once considered unthinkable becomes reality.

As Trump’s repeated authoritarian statements wear out moderate voters’ emotions, they also provide tantalizing red meat to his base. MAGA die-hards are thrilled by Trump’s every suggestion of upending norms in America because they wish to live in a country in which Trump is their all-powerful leader. They want Donald Trump as their Vladimir Putin or their Kim Jong Un.

Trump, Parkhomenko continues,

has told America who he admires, who he is and how he intends to destroy the foundations of our republic. After years of conditioning, many voters will dismiss the former president’s statements as hyperbole and nothing more than “Trump being Trump.” Others will wrongly believe that sweeping changes could never come to pass in America, even if he is elected.

In a chilling analogy, Parkhomenko describes Trump’s efforts to desensitize his audience:

Horror movies become less scary each time they are watched, and Americans have viewed the Donald Trump horror show on repeat for nearly a decade. The villain does not change, but the viewer’s response calms dramatically. No matter what Trump says or does, Americans have seen this movie before, and we’ve seen it so many times that what once shook us at our core is now just background noise.

In this sense, the 2024 election will be a test: Can the Democratic Party, with Biden at the top of the ticket, somehow reanimate and reawaken those voters who have become inured to Trump’s insatiable venality, his relentless obsession with personal enrichment, his unquenchable thirst for wealth and power, his profound lack of moral principle or ethical boundaries, his divisive and chaotic indifference, his inability to feel guilt or remorse, his manipulative and unscrupulous focus on his own advantage — to the exclusion of all others and the public good?