A private email written by Mayor Rahm Emanuel bragging about the now-completed, three-year phase-out of health care coverage for city retirees is taking center stage in the ongoing legal battle to restore the program and a 55 percent city subsidy.

The retirees’ attorney, Clint Krislov, highlighted the mayor’s cavalier reply to an October 2015 email from venture capitalist Henry Feinberg in an Illinois Appellate Court brief filed this week.

The brief makes the case for a preliminary injunction that would compel the city to restore the now-terminated city coverage.

“Since when did Rahm Emanuel let a judicial ruling get in his way and not find a creative work-around solution?” Feinberg wrote then.

Emanuel replied, “Never. Which is why I eliminated retiree health care. Only elected official to eliminate — not cut or reform — a benefit. Thank you very much. A $175 million saving!”

Emanuel has said he “wasn’t bragging” as much as he was “acknowledging how we stabilized” skyrocketing health care costs.

But Krislov didn’t buy the mayor’s argument. His brief brands Emanuel’s email “boasting” and “Trump-like.”

It’s all part of the continuing fallout from the massive information dump that was supposed to end Emanuel’s legal battle to keep 2,700 of his private emails concealed from public view.

“The mayor’s chest-pounding shows two things: That the motivation to cut them off was the mayor’s narcissism and that, even he refers to it as a ‘benefit,’ ” Krislov said Thursday.

“As a ‘benefit,’ it’s protected by the pension-protection clause” of the Illinois Constitution that says benefits may not be diminished or impaired.

Krislov’s brief also takes aim at another sore point for Emanuel: the credibility of convicted former City Comptroller Amer Ahmad.

Ahmad chaired the “Retiree Health Benefits Commission” that laid the groundwork for the phase-out by branding the retiree health care program “unsustainable.”

The report projected that retiree health care costs would have ballooned to $307 million by 2018 and $541 million by 2023 if left unchecked.

“The report is no more credible than its chairman, who now resides in federal prison,” Krislov said. “The city’s actual costs for retiree health care were flat at $100 million-a-year from 1987 through 2016. That means this is not ‘unsustainable.’ It’s not growing.

“If anything, it will decline over the years as non-Medicare retirees are replaced by Medicare-qualified retirees at a 60 percent reduction in cost. The city is crying wolf for something that has been a very manageable expense.”

Krislov’s central argument for restoring the retiree health care program is that more than 10,000 city employees and retirees who started working for the city before April 1, 1986 — and who do not qualify for Medicare — are on their own to search for coverage that’s difficult or too expensive to find.

They have been forced to choose between exorbitant premiums that, in some cases, are double their retirement checks or go without health insurance coverage at a time when they need it the most because of their age and declining health.

“Even if they wanted to qualify for Medicare, they couldn’t. And the city told them, ‘You don’t have to worry about Medicare, you’re on the city plan,'” Krislov said.

The mayor’s office had no immediate comment on the new filing.

In court, the city has not disputed that non-Medicare-eligible employees were told they could rely on the program. Instead, the city’s defense has been that the individuals who offered that assurance were not authorized to make a legally-binding commitment.

After retirees unleashed their anger about the mayor’s private email, Emanuel defended himself.

“You can call what I did heartless. . . . [But] we avoided raising taxes,” the mayor said then. “And we avoided cutting basic neighborhood services. And we still met the objective of providing and giving people health care.

“Over 30 or 40 years, we promised benefits that were never paid for. Not only has this [phase-out] saved the city $100 million. It was gonna grow to $350 million with no revenue source. I wasn’t bragging so much as acknowledging how we actually have stabilized our health care costs for the first time in 30 years.”