First Lady Michelle Obama is venturing out onto the campaign trail to shore up embattled Democratic candidates. Apparently, Lady Macbeth wasn’t available.

First ladies are enlisted because they are the kinder, gentler face of the administration; they represent the president but aren’t responsible for unpopular policies. Americans tend to want to admire their first ladies, even if they are angry with the president. First ladies are almost always Teflon.

A quiet former librarian who would have preferred never to give a speech, Laura Bush campaigned for Republicans in 2006, when her husband’s radioactivity was like that of a nuclear landfill. Laura Bush has a soft Texas accent, a comforting presence, and she wasn’t going to advocate anything more controversial than reading.

Mrs. Obama may emphasize being a mother — or mom, in the current parlance — but she is not comforting, and we remember that in the past she has made incendiary statements: the “first time in my adult lifetime I’m really proud of my country” remark springs to mind. She almost lived that down, but not quite: first ladies who fly to New York on Air Force One for “date night” need to make it clear that ’tis a very great country indeed that lets them have such a nice ride just to see a Broadway play.

The first lady to whom the fashionable Michelle Obama is most often compared is Jacqueline Kennedy Onassis, who was sometimes forced reluctantly into campaign mode, though John F. Kennedy didn’t live long enough to know what really bad numbers were.

But Mrs. Kennedy, like Mrs. Obama, loved to do things up big. “Jackie wanted to do Versailles in America,” said Oleg Cassini, the fashion designer, to author Sally Bedell Smith. Her heroines were Madame de Maintenon, Louis XIV’s mistress, and Madame Recamier, who presided over a sparkling salon. Not exactly Kansas. But she got away with it; it was her popularity that made her such an asset that she was in Dallas that fateful day.

Why could Jackie O get by with it, while Michelle O can’t?

You can say it’s a different time, that there are different expectations of what a first lady is supposed to do, that we didn’t have a Tea Party fed up with the pretentions of the elites then. I don’t buy that. I think what happened is Michelle O rubbed our noses in it, but Jackie O didn’t. Mrs. Kennedy cared what we thought.

She went to great lengths to prevent the public from knowing that Stephan Boudin, the decorator who refurbished the Empress Josephine’s Malmaison, was working in the White House. She tried to convince us she wore more American designers than she did, clandestinely dispatching friends to the Paris collections to buy her wardrobe.

That wasn’t necessary — I have a feeling we would have been proud to know that we had the very best working on our White House. But we like our leaders to share in our joys and travails. Mrs. Obama’s behavior was the opposite of the British royal family eating rations to share the plight of Londoners during the blitz. Lately, Princes William and Harry have taken to flying commercial. And have you ever seen a nicer display of austerity that Queen Elizabeth II, headscarf and all, climbing aboard a train to go to the country?

This is a far cry from taking an ostentatious vacation to Marbella — which is almost synonymous with decadent wealth — when the country is suffering the worst economic downturn any of us can remember. Many Americans were out of work or worried about being out of work, unable or afraid to take a holiday, much less one in a famous hotel, when Mrs. Obama took her vacation. It wouldn’t have changed the unemployment figures if she’d stayed home. But it would have made us feel that she knew what we are going through.

Of course, the Obamas picked up the tab for much of the trip, including food and hotel rooms, but taxpayers didn’t get off scot free. We paid for security — which was necessary but nonetheless hardly a bargain in hard times — and most of the cost of operating Air Force Two, which sat idle on the ground while the Obama party enjoyed lobster with seaweed risotto. It wasn’t Kansas.

I’m sure that George VI and his family weren’t going to starve to death during the blitz, but the people of London deeply appreciated that the royal family wanted, even if only in a small and mostly symbolic way, to share their hardship. Small economies aren’t going to change the world. But it’s the thought that counts, and these actions, possibly meaningless in any economic way, create a sense of shared values. We’re all in this together, mates.

The excess in Marbella fed into the public’s general disgust for Washington extravagance — for a health care reform we can’t afford, for stimulus that doesn’t stimulate, for Nancy Pelosi’s plane with the bottled water, flowers, and liquor, which isn’t Mrs. Obama’s fault, but nevertheless seems part and parcel of the same pattern. It’s not that we’re churlish — it’s that they seem to take us for granted. They don’t seem to care that we’re being forced to cut down on the lobster risotto.

One newspaper headline says that the first lady is “cautiously” hitting the campaign trail. Not cautiously enough, in my opinion. It might be better for Democrats to keep her at home, tilling that organic garden at 1600. She is not Teflon after Marbella.

Charlotte Hays is a Senior Fellow at the Independent Women’s Forum.  Hers is part of our fall series, “Stiletto Nation.”