Cities change. In New York for the past few centuries, two rare constants have been horse-drawn carriages and political corruption. Under Mayor Bill de Blasio, those two may be colliding.

Multiple law enforcement probes are swirling around the Democrat, but perhaps none more intriguing than the one starring ye olde buggies, popular with tourists in and around Central Park. To admirers, the carriage industry is a win-win-win: visitors get a quaint diversion; unionized drivers get a stable middle-class living in the shadows of condos fetching eight figures; and animals get to work when their expensive upkeep could have relegated them to pasture (or worse).

To detractors, the equines are mistreated relics with no business in the asphalt jungle. De Blasio has been a vocal, insistent advocate for banning the horses even as most the mission appears increasingly quixotic: Polls show most New Yorkers would prefer to keep them, and his fellow Democrats on the City Council rejected a ban in February despite fevered efforts from City Hall.

The Mayor vows to try again, but unlike his signature causes of fighting income inequality and implementing universal pre-kindergarten, I’m not sure where he truly stands—if banning horses is a matter of politics or principle for him.

Never much of a public animal-rights activist, he got religion as a long-shot in the 2013 Democratic primary. In March 2010, he wasn’t a sponsor of legislation banning carriages; less than a year later, he had fervently signed on. In the meantime, he got thousands of dollars from a real estate developer who co-founded the anti-carriage group New Yorkers for Clean, Livable and Safe Streets (NYCLASS). Well more than a million dollars would follow—to de Blasio or, more importantly, to a shadowy group dedicated to sinking his top rival, Christine Quinn.

Now, amid sprawling investigations that appear directed at City Hall, federal and local law enforcement have subpoenaed NYCLASS, along with top de Blasio advisers, including one who charged with shepherding the carriage ban through the Council. City Hall has denied wrongdoing; a spokesman says, without noting the contributions, that the Mayor’s “commitment to removing horse carriages from city streets is well-documented, far predating the start of this administration.” Investigators, including the crusading U.S. Attorney Preet Bharara, are declining to comment but it appears what they are looking for a transgression older than Tammany Hall: pay-to-play politics for a pricey piece of Manhattan real estate.

“It has nothing to do with the horses—it never, ever was,” says carriage driver James McDaid. “We knew from the first day it was all about real estate.”

Real estate in the form of stables. Like the carriages they house, the stables appear as relics: stout brick buildings, spilling hay next to glassy apartment towers and blocking other lucrative investments from rising above where they stand.

McDaid, who hasn’t lost his County Donegal brogue, has been ferrying tourists for nearly three decades. In 2001, he and 12 fellow carriage owners pooled limited resources to buy a cooperative stable on West 52nd Street. It wasn’t cheap then, but it’s become vastly more valuable since as the Far West Side of Manhattan has become a boom town.

“All we ever wanted to do is go to work,” he said. “That’s why we had to buy that stable. It was very expensive property at the time—and nobody really had much at that time. And we all scrimped and scrapped and there’s a big mortgage to be carried there, and we’ve got a big staff. So the stable has been a success for us in the sense that it keeps our business driving. That’s the name of the game: keep the business alive.”

Stephen Nislick, the press-shy developer who made his fortune in parking garages and co-founded NYCLASS, has long sworn that his concern is for animals only. But documents I recently obtained through a Freedom of Information Request included a NYCLASS presentation to City Hall noting the city could get far more in taxes if the stables were redeveloped. Other official documents I found noted the location and building classification of the four stables.

NYCLASS, in a statements, says: “Electric carriages could have been a winner for the stable owners and drivers had they wanted it. No one at NYCLASS has ever had any desire to buy the stables; we just didn’t want stable owners or drivers to lose money.”

There are other ways that Nislick and NYCLASS hurt themselves. The New York Post reported that he was caught on tape extolling campaign contributions as “the best investment.” At that time, Nislick was showering Quinn with cash in the hope she would change her position supporting the carriages.

When that didn’t work, a consultant then working for the group threatened a Quinn aide with an independent political campaign against her if she didn’t change sides, another Quinn aide tells me. (The Daily News, which champions the carriages, reported last year that the FBI is investigating the incident as possible extortion).

NYCLASS has since been fined more than $26,000 for campaign finance violations.

And Last April, Nislick also threatened to hit a Daily News photographer in her face, the paper says.

The mayor’s actions don’t, of course, rise to that level, but plenty object to the ways he sought the ban, which he had vowed as a candidate to pass on the first week of his administration. At the very least, he could have followed through on another pledge: to actually visit the stables. I have no opinion whether carriage horses should be banned or not, but more information always benefits weighty decisions affecting so many people, and animals.

More regrettable is how the Mayor simultaneously laments and reaps the Citizens United Supreme Court decision, which loosened independent groups’ abilities to sway elections.

“I believe there should be a constitutional amendment to reverse the impact of the Citizens United decision by the Supreme Court,” he said last November. “I think there’s a whole lot of other things that should happen to reduce the flow of money into public life in general.”

I heard no such peep when Citizens United helped him in the form of the NYCLASS-tied group knocking out Quinn with misleading advertisements. Nor did he publicly gripe about the independent group he created, Campaign for One New York, also an apparent subject of law enforcement investigations.

Call me naïve but the honorable method may have been calling off all independent groups in his name, realizing that Quinn’s close ties to then-Mayor Michael Bloomberg were already making her vulnerable in the primary.

De Blasio instead argues that reform can only come by winning in the existing system, that he can’t stop using dark money to cut deals when the law allows others to just that.

“Here’s the problem—the law,” he told WNYC’s Brian Lehrer Friday. “We are following the law.”

Those investigators looking at his administration will have to judge that.