Acting Philly Police Commissioner Christine M. Coulter stumbled last week like a rookie cop on her first traffic stop.

It happened after an old photo surfaced of her wearing an offensive T-shirt that read, “L.A.P.D. We Treat You Like A King.” Coulter should have begun by taking immediate responsibility and apologizing for wearing something so racially insensitive. That’s just Crisis Management 101.

But when an Inquirer reporter asked her about what the slogan on the T-shirt meant, Coulter tried to play it down, responding, “I can’t remember giving it a thought. But I certainly can’t say I thought it meant Rodney King."

Her response wasn’t plausible. I lived through the 1990s, just as she did. If the T-shirt hadn’t been a reference to King, a black motorist who was severely beaten by four white officers in 1991 on a Los Angeles freeway, then what exactly had it been a reference to?

King’s beatdown, which became a widely seen video, was a symbol of America’s lingering racial problems. After the officers were acquitted and rioting broke out, his “Can we all get along?” plea restarted a national conversation about police brutality. I once met King at a party at the old Water Works Restaurant on the Schuylkill and made it a point to shake his hand.

I think Coulter understood exactly why the wording on that shirt was offensive, particularly for the era. Instead of apologizing profusely for donning it, and perhaps explaining it as a youthful act by a female cop trying desperately to fit into a predominantly white male bastion, she deflected.

“I’m very frustrated that someone wanted to take what’s arguably a picture of me and two old friends and turn it into something, you know, ugly or mean-spirited,” Coulter said.

It gives me no joy to write this. As a woman, I had been rooting for her, because it’s way past time for a qualified woman to lead the nation’s fourth-largest police department. Having a female in charge could make a statement and help improve the culture on the force. But her handling of the T-shirt photo has been an epic fail for Coulter, who was appointed after Richard Ross abruptly resigned last month.

In addition to admitting culpability, she should have issued a public statement formally apologizing to King’s family (he died in 2012).

Coulter also should have directed an apology to the Los Angeles Police Department and to the City of Los Angeles. She should have posted it on social media or held a news conference, as Ross did when he apologized for his initial remarks via Facebook video following the arrests of two black men at a Starbucks near Rittenhouse Square a year ago.

We need to be reassured that she understands why that shirt was not OK. We need to see her promise to do better, especially if she is named the city’s first female police commissioner.

After all of the racist and misogynistic Facebook posts that led to the firing of seven police officers last month, we want to know that the new commissioner will follow Ross’ lead and not tolerate that kind of behavior on social media or elsewhere.

Chad Dion Lassiter, executive director of the Pennsylvania Human Relations Commission, agrees.

“I would recommend that the department go with a qualified woman who understands the culture of sexual harassment and the anthology of police brutality, and what needs to occur to break the blue wall of silence of both and deal with the historical challenge of trust vs. mistrust,” Lassiter told me Wednesday. “This interim police commissioner doesn’t fit any of the above at the present time.”

I’ll bet Coulter hopes people forgot all about this issue over the long holiday weekend, but the longer this drags on without her addressing it, the worse that photo looks.

She needs to step up quickly or risk being remembered for having made a racist fashion statement.