So now Preet Bharara has cast a gimlet eye on Bill de Blasio’s campaign fund-raising.

Which comes as no surprise. If de Blasio isn’t running one of the gamiest administrations since Tammany’s sachems were pulling the strings at City Hall, it isn’t for lack of trying.

But not to worry.

As mayoral operative Dan Levitan says: “We are fully confident that the campaign has conducted itself legally and appropriately at all times.”

“And if it turns out that it hasn’t,” de Blasio himself quickly added, “it’s all on the campaign and I didn’t know anything about it. It makes me so mad when things like this just happen.”

Ha ha. Only kidding about the Blas part.

For the time being, anyhow. Because if there is any pattern to the de Blasio incumbency, it is this: Bad news, of which there is more every day, is ­always somebody else’s fault.

The negative headlines last week about his near-shutdown of construction on the city’s third water tunnel, he says, are the result of “miscommunication” — not the inexcusable slowdown itself.

Just as the city’s decision to allow campaign-contributing developers to flip a Lower East Side nursing home for condo construction happened without the mayor’s knowledge.

“It makes me livid that this happened in one of the agencies of my administration,” declared de Blasio (for real). “This just should not have happened, and there will certainly be consequences.”

And there may well be, but probably not of the sort that the Blas had in mind.

Indeed, given Bharara’s performance to date — Shelly Silver and Dean Skelos go before federal judges for sentencing Wednesday — the prosecutor’s interest in de Blasio can only be stirring mayoral nightmares.

The Post’s Jamie Schram and Larry Celona reported Saturday that Bharara has opened a probe of deep-pocketed real-estate developers allegedly involved in the city’s expanding NYPD scandal — which, actually, could turn out to be a twofer for Preet, and double trouble for de Blasio.

Certainly, de Blasio’s brainchild Campaign for One New York will get a look. That’s the independent, unaccountable not-for-profit slush fund that harvested more than $5 million from folks with business before the city before the mayor moved to shut it down late last month.

It has all been legal, or so the mayor has insisted.

But, again, Bharara appears to be setting himself up to be the final arbiter. Which, again, must be sending shivers down the mayoral spine. The prosecutor, after all, has made a ­career out of busting not-for-profit fraud.

This time de Blasio may have no one to blame but himself.