Perennial late-night class clown David Letterman has at last apologized to Alaska Gov. Sarah Palin and her family for his “flawed” joke about her daughter.

In my effort to promote civility and manners, I’m not going to repeat the joke itself. If you didn’t hear what Mr. Letterman said last week, just think back to sophomore year in high school and recall the tasteless humor of the smarmiest guy you knew. It was that sort of thing.

This wasn’t the first time Mr. Letterman got his audience laughing at the expense of Mrs. Palin. In fact, crude and crass remarks about her are a staple in Mr. Letterman’s humor pantry, such as it is. Probably, the governor has quickly grown accustomed to the unwelcome attention of comics like Mr. Letterman, whose obvious bias, coupled with his juvenile sensibilities, combine to reveal both his politics and his lack of imagination.

Last week’s attempt at humor, however, landed Mr. Letterman in the woodshed, or so one would assume, since initially he didn’t seem to think there was anything wrong with making sex jokes about teenage girls. (Apparently, Mr. Letterman isn’t familiar with the label “creeper,” the word used by teenagers to describe 62-year-old men who do this.)

In fact, according to reports, even Mr. Letterman’s mother, Dorothy Mengering, thought his rude joke stepped over the line this time.

Unfortunately, Mrs. Mengering’s son doesn’t seem to have learned how to deliver an apology. At least, the 3- 1/2 minutes he offered up on Monday wouldn’t have passed muster in my house.

Why? For starters, an apology ought to be about the person you offended, not just about yourself.

Mr. Letterman’s apology, which the governor graciously accepted on behalf of her family and women everywhere, included 31 uses of the personal pronoun “I” – an average of one every 11 seconds, but never once mentioned the ramifications of his actions for the governor or her family.

In his mea culpa, he said his intent (to insult Mrs. Palin’s 18-year-old daughter, rather than her 14-year old) was unimportant, only the perception created by his bad joke, for which he took responsibility. Essentially, he said he was sorry that his joke was misunderstood.

“As they say about jokes, if you have to explain a joke, it’s not a very good joke,” Mr. Letterman said. Except in this case, even if his intent had been clear, the joke would have bombed.

We parents hear these sorts of apologies all the time. One child says something unkind to another one, and what follows is something like, “I’m sorry you’re so hormonal and testy,” or “I’m sorry you’re a humorless nerd.” Or my favorite, “I’m sorry you’re such a jerk.”

It’s the apology that makes everything … worse.

I imagine Mrs. Palin was relieved to receive at least some acknowledgment that her family had been so rudely offended, but Mr. Letterman obviously comes from the “mistakes were made” school of personal responsibility. It’s an arms-length accountability that makes you seem heroic just for feigning regret.

Mr. Letterman could have said, “The joke I made at the expense of Gov. Palin and her daughters was offensive, thoughtless and unkind. I deliberately tried to embarrass them, and the fact that Gov. Palin had to ask for my apology on a competing television network further showed my insensitivity and immaturity.

“I ask her forgiveness and that of her daughters and husband, and I promise never again to make jokes at the expense of the Palin family.”

Then again, think back to high school. The class clown never did get it, and this one still doesn’t.