It’s hard to imagine that President Biden would take to heart the advice dispensed this week by Mayor de Blasio in a mea culpa in the Atlantic. “I made my fair share of mistakes,” Mr. de Blasio writes, describing himself as “unfortunately somewhat of an expert” at “being unpopular.” He suggests that Mr. Biden learn from his failure to convey a hopeful message to voters in time to right his presidency before the midterms.

This is a sad bit of vainglory from Hizzoner. Mr. de Blasio fails to see that it was not errors of messaging but of policy that made his administration such a disappointment. He contends “I let a focus on individual initiatives, no matter how noble or substantive” distract him from “offering an overarching vision for the future.” It’s more accurate to say voters saw the future Mr. de Blasio had in mind for New York City, and rejected it.

That’s not how Mr. de Blasio, whose approval rating was running around 25 percent toward the end of his tenure as Mayor, sees it. “Things started out right for me,” he writes. He chalked up his 2013 win to his vow to “fight against a status quo that didn’t work.” Invoking class warfare, he promised New Yorkers “to tax the wealthy so their kids could have free pre-K.”  After that early policy move, he writes, things went downhill.

“I encountered crisis after crisis during my eight years as mayor,” Mr. de Blasio writes, pointing to “crumbling public housing, dysfunctional jails, tensions between police and communities.” He contends he “tried to address each in great detail.” His focus on problem-solving, as he sees it, led him to go “days or weeks” without explaining how it all tied back to “my original mission: making New York better and fairer for everyone.”

The erstwhile mayor regrets he “should have walked among” New Yorkers “rather than just working for them behind closed doors.” Even so, we hardly recall Mr. de Blasio maintaining a monk-like reclusivity as Mayor. We do recall the frustration of countless New Yorkers with his failure to contend with the pressing quality of life issues of the day, particularly in regard to the public school system and the jump in crime.

An appraisal by a Manhattan Institute fellow, Tevi Troy, at the end of Mr. de Blasio’s mayoralty underscores the extent of his shortcomings. Noting his hostility to charter schools, efforts to undermine the city’s gifted and talented education programs, and unblinking support for teachers unions, Mr. Troy notes the “racial achievement gap worsened” in public schools, and enrollment declines signaled parents looking for alternatives.

While Mr. de Blasio’s choice of Bill Bratton as police commissioner initially enabled the city to hold the line on crime, in the aftermath of the 2020 George Floyd protests Mr. de Blasio embraced the “defund the police” slogan, Mr. Troy writes, and the city began to see the stirrings of what has become a sustained increase in public disorder and criminality harking back to the days before Mayor Giuliani cleaned up the city.

None of that can be found in Mr. de Blasio’s Atlantic article. Instead, his lament is that “I had one of the loudest megaphones in the country, and I failed to use it properly.” Hence his suggestions for Mr. Biden, whose “bully pulpit is a thousand times more powerful.” He urges the president to “use it to show that he truly empathizes with everyday Americans” on problems like “inflation, public safety, and affordable health care.”

Yet Mr. Biden’s empathy is not much in question. Even so, we understand the temptation for Democrats to take the failed mayor’s advice. As his poll ratings sink, they’ve tried to pin their party’s unpopularity on the idea that “Democrats are terrible at messaging,” as Senator Gillibrand has contended. These Democrats, including Mr. de Blasio, just don’t have it in them to give voters credit for realizing when failures of policy are failures of politicians.