She devastated him by implication. If Romney was the son of privilege, she and her husband were anything but. What she said directly is that Barack Obama understands people who are struggling. What she didn’t have to say is Mitt Romney doesn’t.

As a general matter, her speech was a big hit: good enough that even Fox News was kind to her. But the specific stories — about her father working through the pain of multiple sclerosis, about the debts she and her husband accumulated from college — served a powerful campaign purpose. A speech that was thoroughly apolitical on the surface carried multiple political messages, linking a very traditional message about parenting with a call for social justice.

And it was almost entirely done though personal stories.

“And when my brother and I finally made it to college, nearly all of our tuition came from student loans and grants,” she said at one point. “But my dad still had to pay a tiny portion of that tuition himself. And every semester, he was determined to pay that bill right on time, even taking out loans when he fell short. He was so proud to be sending his kids to college…and he made sure we never missed a registration deadline because his check was late. You see, for my dad, that’s what it meant to be a man.”

Among the many messages here: Her dad was awesome; he was also a traditional father; and, more broadly, people who receive government aid can be, usually are, very responsible citizens.

Another nice riff on student loans came later: “And believe it or not, when we were first married, our combined monthly student loan bills were actually higher than our mortgage. We were so young, so in love, and so in debt.” I suspect this drew a lot of laughter in living rooms.

Oh yes, and she also said that for husband, “success isn’t about how much money you make, it’s about the difference you make in people’s lives.” Did any other presidential candidate come to mind as perhaps having a contrasting approach? Michelle Obama was much too polite to say. She didn’t have to.

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