(CNN) New York Mayor Bill de Blasio's longshot presidential campaign rollout was greeted on Thursday morning with a loud and persistent round of Bronx cheers from police union protesters, a bitter welcome from old rivals eager to dampen his new endeavor.

Their heckling, which briefly interrupted his first national interview as a candidate -- and which he acknowledged on-air as "a little serenade" -- came from a familiar foe with contract concerns. But the complaints about the mayor's handling of his day job are both broader and more deeply rooted in a city hungry for near-constant attention from its leader.

After all, de Blasio is running -- for president and away from the town that twice elected him.

There are greener pastures up ahead, at least as the New York Democrat sets off now to make his way through the Iowa farmlands, but with no promise of a kinder reception. What seems certain is that his decision to hit the presidential hustings is an unpopular one with the folks at home. More than three in four New York City voters said in a recent Quinnipiac University poll that he should pass up a run.

The boo birds were out on Thursday, and not just his serial detractors from the police force. Public Advocate Jumaane Williams, the Democrat who would ascend to acting mayor if de Blasio were absent for nine straight days (or take his job if the naysayers are proven wrong and de Blasio wins), was critical during a morning interview on a local station.

"If you're going to run for president, you've got to fix these things here first," Williams said, "or there's going to be a lot of noise explaining why you shouldn't be."

That sort of noise has steadily risen throughout de Blasio's second term, as his efforts to up his national profile became increasingly apparent. The local papers -- the New York Post and Daily News, mostly -- have trailed him during his travels to early voting states, often returning home with stories celebrating his stumbles, like the time he got caught in an Iowa blizzard , or, as happened during a recent visit to New Hampshire, gleefully reporting on the sparse audience at a roundtable event on mental health.

"There were also about six reporters on hand," the Post noted, "to make the room at the Sugar River Valley Regional Technical Center look a bit less empty."

Still, de Blasio is betting on himself. He is no stranger to doubters' mocking his ambitions. He was no one's favorite to be elected mayor in 2013, but four years later stormed to a second term in a landslide.

That New York mayors rarely go on to bigger jobs is a truism of city politics. Asked about it during a session with reporters on Thursday afternoon, de Blasio suggested a new political reality could yield surprising results.

"Actually, (there were) only a couple of people who ever tried to seek higher officer and I think each of them had their own challenges," de Blasio said. "But the truth is we're in an entirely different time. What we used to think of as the ground rules of the democratic process don't exist anymore. And we've seen in the last few years that people all over this country are looking for change."

With the Statue of Liberty looming off in the distance beyond him, de Blasio jabbed President Donald Trump a few more times-- he's determined to nickname him "Con Don," a phrase he repeated throughout the day -- and touted his estimable progressive record, before saying farewell, for now, to reporters and setting off for Iowa.

It felt, if only for a moment, like the end of an era.

De Blasio's troubles with the tabloids have been long-running and reliably colorful. When "Hizzoner" (as in, "his honor") at the Staten Island Zoo early in his first term fumbled "Charlotte," a fill-in creature for Groundhog Day celebrations who reportedly later died as a result, the Post declared that de Blasio had "groundhog blood on his hands."

The mayor's morning schedule has been a more reliable source of ugly headlines. He often rides -- and not on the subway but via motor vehicle -- from Manhattan to a gym of choice in Brooklyn, his home borough. De Blasio also has a reputation for tardiness -- so much so that New York Magazine saw fit to publish a list of his late arrivals before the end of his first year in the job.

Add that to de Blasio's ongoing feud with New York Governor Andrew Cuomo -- each giving as good as he gets -- and there is no shortage of meat for the New York City press corps to pick at, and that's without diving into his controversial handling of the troubled New York City Housing Authority or allegations of corruption in City Hall. (De Blasio has never been charged with wrongdoing.)

Trump, a lifelong New Yorker, poked back at de Blasio on Thursday, calling him "the worst mayor in the history of New York City, and without question the worst mayor in the United States."

"It will never happen," the President said of de Blasio's electoral chances. "I'm pretty good at predicting things like that. I would be very surprised to see him in there for a long period, but it's just not gonna happen. If you like high taxes, and if you like crime you can vote for him. But most people aren't into that. So, I wish him luck, but really, it'd be better off if you got back to New York City and did your job for the little time you have left."

But for all the negative stories, the mayor won re-election comfortably in 2017 and, more to the point, did not draw a serious primary opponent as he romped to the Democratic nomination with nearly 75% of the vote.

"Nobody legitimate stood up to challenge him for a reason -- they all polled and they all realize that regardless of what the political pundits and the chattering class in the press says, at the end of the day, people will vote for him because they look at their wallets," a former de Blasio aide told CNN, noting his popularity outside of Manhattan and among minority voters. "In the other four boroughs, where they were ignored or maligned or demeaned by Giuliani and Bloomberg, de Blasio actually delivered for them. When it comes to affordable housing or universal pre-K or aggressively reducing the amount of stop-and-frisk, they feel this man finally spoke for them."

Even now, with his overall approval rating down to 42% in the Quinnipiac poll , de Blasio's numbers with black voters remain undeniably strong -- with 66% approving. Among Hispanics, there is 40%-40% split. Disapproval among white voters is what drives down the total: Nearly six-in-ten are down on his performance.

A former aide to de Blasio's predecessor, Michael Bloomberg, told CNN on Thursday that the mayor's first campaign put him in a hole with some voters that he's been unable to climb out from.

"He came into office arguing he was the biggest change from the Bloomberg years, the biggest change from the past. He ran against the past. And then in his inaugural address, he specifically excoriated the previous years," the former aide said. "His view is that the market-rate housing that was built post-9/11 should not have been built and it should have been affordable housing. And in a lot of cases, that got interpreted as hostile to the people in the market-rate housing."

De Blasio's message -- which he formulated then as "a tale of two cities" -- still stings, the former aide said: The people living in those new, often more expensive apartments "heard de Blasio running against the status quo as a repudiation of them, which once you hear is hard to un-hear."

His conflicts with the press, both of the aides separately concluded, came down to de Blasio's fundamental frustration with what he views as frivolous stories and petulant reporters.

"Every elected official, particularly ones in the executive who are running something are frustrated that the media works differently, that there's not enough substance," the former Bloomberg aide said. "There's hardly an elected official who doesn't think there's enough substantive coverage."

The question, though, is how de Blasio has handled it. His own former aide put it diplomatically: "I think there's just different strategies of dealing with the press and, in some worlds, you have your flack be more aggressive and the principal is less aggressive on the record."

"But the mayor," his old aide said, "has obviously chosen a different tack."

So what does it all mean for his presidential hopes? There isn't much optimism -- unless you count the evident certainty that he will fail, perhaps spectacularly -- among New York politicos. There is a similar confidence, even among friends, that his media troubles will, literally, follow him wherever he goes.