Perhaps someone will be good enough to tell me how fat you are allowed to be before your opinions no longer matter. Surely conservative radio host Laura Ingraham had a specific weight in mind when she attacked Sen. John McCain’s daughter, Meghan McCain, essentially dismissing her for being, in Ingraham’s eyes, overweight.

For those who missed the recent contretemps, it unfolded as follows:

First, Meghan McCain blogged that she is no fan of Ann Coulter: “I find her offensive, radical, insulting and confusing all at the same time.”

Whereupon Ingraham took up for Coulter: “Do you think that anyone would be talking to you if you weren’t kind of cute and you weren’t the daughter of John McCain?” she asked, in her best Valley Girl accent. Speaking as Meghan McCain, she added: “‘OK, I was really hoping that I was going to get that role in the ‘Real World,’ but then I realized that, well, they don’t like plus-sized models.”

McCain responded succinctly on ABC’s “The View”: “Kiss my fat ass.”

For her part, Ingraham first tried to ridicule the angry response to her gratuitous insult, asking rhetorically if it was OK to tell McCain to “lighten up.” When that didn’t work, she resorted to revisionism, saying on Fox News, “Let the record show: I never called Meghan McCain fat.”

She is telling the truth, of course – in the same weaselly, disingenuous way Bill Clinton was telling the truth when he said, “I did not have sexual relations with that woman, Miss Lewinsky.”

Ingraham went on to add the boilerplate: “This contrived flap is not about me or Ms. McCain. It’s just another left-wing attempt to silence any criticism of the liberal agenda.” I suspect she would say the same if her sink were clogged.

Apparently, she finds it easier to believe herself the target of some globe-girdling liberal conspiracy than to accept that she defined, demeaned and diminished a young woman based not on what she said, but on the fact that she said it while carrying more poundage than Ingraham approves. And beneath the cattiness, there is a serious issue here. I mean, if Ingraham believes McCain was off target and that Ann Coulter is actually a rational and even-handed observer of the day’s events … well, it’s hard to imagine anyone saying that with a straight face, but for the sake of argument: If that’s the way Ingraham feels, why not make that case? Why not say Meghan McCain is wrong, is foolish, is jealous, is mistaken? Why suggest instead that she is too fat to be taken seriously?

That’s cruel.

If a man did it, he would be called a sexist. I asked my friend Michelle what a woman who does it should be called. “An embarrassment,” she said. “Insecurity with a really big salary,” she said

It would be a mistake, she added, to believe that habit of clawing at one another in such a raw and visceral way is characteristic of all women. But it is characteristic of many.

As the father of a young woman, I resent the idea that she moves through a world where her worth is often defined solely and completely as a function of her physicality. That some men do this angers me. That some women do perplexes and appalls.

But if that’s truly the way of things, Ingraham could do us all a favor by providing hard numbers. How fat can a woman be, how much gray is she allowed, how big or small must her cup size be … in short, how far afield can she stray from the perfect icon of American womanhood Laura Ingraham apparently represents, before she forfeits the right to be taken seriously?

Or perhaps we can agree that a woman’s physicality has no place in a debate about her opinions. After all, Ingraham could stand to lose a little fat herself.

Right around the mouth.

Leonard Pitts Jr. is a columnist for The Miami Herald. His e-mail address is: lpitts@miamiherald.com. Leonard Pitts will be chatting with readers every Wednesday from 1 p.m. to 2 p.m. EDT on www.MiamiHerald.com.