She neutralized her own vulnerability on inexperience by skewering Obama's admittedly thin background.
And she did it wearing a skirt, which means that her opponents will have to tread carefully instead of aggressively challenging her politics and personal background.
All of which emphasizes the huge mistake Obama made by not naming Hillary Clinton - or another qualified woman, for that matter - as his running mate.
For one thing, the selection of Palin would have been less than historic, with one woman already on the ballot.
Not to mention that, most likely, she wouldn't have been on the ballot in the first place.
McCain picked Palin in a cynical ploy to lure disaffected Clinton supporters, and there wouldn't have been any if Clinton were running for vice president.
But now the male-only Democratic ticket has to treat Palin, a small-town "hockey mom" and mother of five, with kid gloves, or risk being seen as bullies.
Clinton could have dropped her with a knock-out punch, no gloves necessary.
Harvard University's Barbara Kellerman stipulated that no one could have anticipated that McCain would have put a woman like Palin on the ticket, but she agreed with my theory.
"Women are able to, and in fact do, take on women in a way that men are now precluded from doing," said Kellerman, an expert on leadership who holds a chair at the John F. Kennedy School of Government.
"The men who did take on Clinton early in the campaign - Chris Matthews or [Mike] Barnicle, the whole MSNBC crowd - have since shut up.
"They shut up in the last stages of Clinton, and they're falling all over themelves now to praise Palin."
Kellerman also cited the example of former U.S. Rep. Rick Lazio, who ran against Clinton for the Senate.
"Lazio attacked her, but in doing so, he brought down the wrath of God on himself," Kellerman said.
"Women rush to the defense of other women when they are attacked by men; they're less inclined to do so when attacked by other women."
And who doesn't think Clinton would demolish Palin in a vice-presidential debate?
"I think if
you're hypothesizing a debate, Clinton's strength would without question come to the fore, and that's her formidable intelligence, familiarity with various policy issues and capacity as a lawyer to attack the opposition," Kellerman said.
Joe Biden also could mop the floor with Palin, but now he has to be gentle and circumspect while doing it.
Palin, of course, is "no shrinking violet," said Debbie Walsh, director of the Center for American Women in Politics at Rutgers.
"I don't think she's going to fade away and cower under whatever Biden may dish out. But I think it's going to be a balancing act, and he'll have to handle it very carefully.
"He's going to have to be aggressive, but how aggressive can you be? And that's going to be the challenge."
U.S. Rep. Allyson Schwartz disagrees that men with female opponents are at a disadvantage, citing the Obama-Clinton primary.
What galls her, though, is McCain's presumption that a "very extreme conservative who plays to the right wing of the party" would be able to lure women to the Republican ticket just because of her gender.
"Here's a woman who doesn't believe in choice, in equal pay, in the separation of church and state, who believes in creationism . . . and she's going to appeal to Clinton supporters? How could that be true?"
What infuriates me is seeing the likes of Sarah Palin reap the rewards of the feminist movement, the very tenets of which she disdains.
"I hate her," several of my normally rational friends said yesterday morning.
It was a bad case of Post-Palin Depression. *
E-mail porterj@p'hillynews.com or call 215-854-5850. For recent columns: