NEW YORK– In one week, Michelle Obama sat for a formal White House portrait, dressed in somber, tailored clothes; posed for a snazzy People magazine cover, dressed in a slightly down-market, hot-pink lace outfit that showed plenty of skin; let the national media know that the First Family would be getting its new puppy from a rescue shelter; and had her press office mention casually that "secretaries and policy makers” had been invited for popcorn and movies at the White House.

That same week, in the midst of the worst economic crisis since the 1930’s, a national poll found that support for President Barack Obama was remarkably high, with respondents consistently saying that he "cares about people like me.”

These two phenomena are closely related. Almost from her first appearance in the public eye, Michelle Obama has used clothing, etiquette, and such cues as where she shops and entertains to send out a subtle but radical message to American voters and to the world.

For the first time since the days of Andrew Jackson, the White House is aggressively "democratizing” the highest office in the land, and symbolically inviting in the common man – and now the common woman.

In other words, Mrs. Obama is managing to set herself up, unprecedentedly, as the "people’s First Lady.” She has carefully studied not only Jackie Kennedy – a comparison obvious from her sheath dresses, boat collars, and page-boy haircut – but also the triumphs and failures of that other glamorous but underestimated stealth radical, Princess Diana.

Princess Di’s legacy in generating iconography that opened the way to tremendous social change is grossly underappreciated.

In her brief lifetime, she was often lauded for qualities (her beauty and style) that were secondary to her life’s work, and derided for other aspects of her character (her emotionality and chaotic personal life) that were equally beside the point.

As a result, few people noticed how genuinely, powerfully transformative her agenda was, how well she had thought it out, and how audaciously she sought to manage it.

Without a formal education, Diana self-consciously set about pushing open the doors of an encrusted monarchy, challenging the sanctities of a long-established class structure, and affirming the value and immediacy of a Britain that was more diverse and socially mobile than ever before. Sometimes her efforts were heavy-handed, as when she embraced AIDS victims physically as a metaphor for social inclusion; sometimes they backfired, as when her shared intimacies with servants provided fodder for a flood of posthumous tell-all books.

But, again and again, by showing up for Elton John and not just for the ballet, or by taking her sons away from the hunting preserve of Balmoral to careen down a waterslide at a tacky amusement park, she told ordinary Britons that their world was as important as any other. She told them that she wanted to know them, and that she wanted her sons to know them, too.

It was this radical popularizing/democratizing mission – not her knowledge of her former husband’s secrets or her later intimate relationship with a Muslim – that made her such a threat to the British establishment.

And she was successful: she taught leaders that they would have to invite the people in – and treat them with basic respect – if they were to maintain their position.

So, what Michelle Obama is doing is not trivial. It was not an earth-shattering policy revelation when she astutely followed reports of Sarah Palin’s $150,000 wardrobe by remarking casually on a late-night talk show that she was wearing a chain-store brand, and that "you can get lots of cute things online.” But it was nonetheless a powerful statement, especially to women, that said: I am not Nancy Reagan, dressed in Galliano, living in a gated community; I am not Mrs. Clinton, disregarding such things because I must argue major cases or run states; I am you – busy, on a budget, overworked, shrewd, cute, clever, finding a way.

Likewise, her invitations to the White House are being used for populist messaging. Who came over to watch the White House chef with Mrs. Obama? Local cooking school students. Who sang at a White House event? Local public high school students.

Again, "secretaries and policy makers,” not "policy makers and secretaries,” are coming over for film night. She is deliberately, coolly signaling that secretaries are just as good and important as policy makers, if not more so.

This is a guest list that says to an anxious electorate: I respect you, wherever you are on the socioeconomic scale. Many White House speechwriters have used that rhetoric, but almost no First Ladies have walked the talk and passed the popcorn.

When I worked on messaging for Al Gore’s 2000 presidential campaign, I often argued with white, older, affluent, male advisers who cared intensely about what was said in the elite media but ignored the popular venues to which most Americans pay attention.

They had learned nothing from the right, whose candidates knew how powerful the right colors, clothing, imagery, and even lighting can be, and how strongly personal narratives – Ronald Reagan in riding boots, or George W. Bush in a flight suit – resonate with voters.

Meanwhile, the nerdy, wonky left kept issuing data points, policy summaries, and white papers – and generally, since Clinton, kept losing – until a young couple showed up and understood that Americans don’t just read; they watch.

You can tell the nation more about your values by saying where you will seek a dog for your daughters than you can through reams of unread position papers.

At a time of crisis, the Obamas are sending a powerful message, and Mrs. Obama, as the female archetype who has picked up Princess Di’s dropped baton, is instrumental in crafting it: no matter who you are, how stressed, how broke, there is, figuratively speaking, a seat in the White House with your name on it.

Naomi Wolf is a political activist and social critic whose most recent book is Give Me Liberty: A Handbook for American Revolutionaries.